Transportation Refrigeration System with Integrated Power Generation and Energy Storage

ABSTRACT

A thermal energy storage system that enables the discharge of refrigerated air for cooling cargo or passengers in large compartments, such as the trailer of a semi-truck, for a period of time well in excess of several hours. The thermal energy storage system is able to provide refrigeration without operating a conventional VCC unit, the truck engine, or the TRU diesel APU engine during all or a significant portion of the period of the typical range of time that a 53 foot refrigerated the truck is traveling over the road. The thermal energy storage system includes a phase change material reservoir, a cooling system-to-working fluid heat exchanger in fluid communication with the phase change material reservoir, and a phase change material-to-target heat exchanger in fluid communication with the phase change material reservoir. The phase change material reservoir contains a phase change material, a working fluid and a working fluid-to-phase change material heat exchanger.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/266,828, filed on May 1, 2014, now U.S. Pat. No. 9,389,007, which isa continuation-in-part of U.S. application Ser. No. 14/151,653, filed onJan. 9, 2014, which claims the benefit of U.S. Provisional Application61/750,789, entitled, “Flexible Thermal Energy Storage forTransportation Refrigeration”, filed Jan. 9, 2013, the contents of whichare herein incorporated by reference.

FIELD OF INVENTION

This invention relates to thermal energy storage devices, refrigerationsystems and methods. More specifically, this invention relates tothermal energy storage and power systems for transport cooling andrefrigeration at a desired temperature range or set-point over extendedperiods of time.

BACKGROUND OF THE INVENTION

A number of systems have been developed over the years to providemulti-temperature refrigeration for the transport of perishable ortemperature-sensitive goods in large trailers or containers. The systemsare generally designed to work both while the trailer is parked andduring operation on the road. These systems, referred to as “trailerrefrigeration units” (TRU) in the trucking industry, are predominantlyvapor compression cycle (VCC) refrigeration units driven by dieselauxiliary power unit (APU) engines (directly or through a gen-set) forlarge 53-foot trailers. On smaller trucks the refrigeration systems maybe powered by truck alternator-produced electrical energy or by APUdiesel engines. The temperature ranges required for transport of themost common refrigerated goods generally range from about −20° F. toabout 40° F. The cooling capacity must be provided for at least severalhours when operating over the road.

Existing VCC TRU systems with diesel APUs have been used for many years.However, APU-powered TRU systems have some significant shortcomings.First, these systems are characterized by high operating costs due totheir large consumption of diesel fuel. Second, operation by use ofdiesel fuel raises a number of regulatory issues, including noiserestrictions and proven health critical emissions from the dieselengines.

Electrical trailer refrigeration units powered by truck alternators areanother one of the systems providing multi-temperature refrigeration,but these systems have been generally limited to smaller trucks and boxtrucks. In other applications, such as with a large 53-foot trailer,these systems have proven nonviable because of the constraints ofdelivering power from the truck to the trailer due to impractical powertransfer and operational logistics issues. The impracticalities in powertransfer from the truck include the significant power generation costand issues in packaging the systems on the truck itself. There are alsosignificant concerns with transferring high voltage or current from thetruck to the trailer. In the shipping industry there is often a split inthe ownership of the vehicle and the container it is transporting. Forexample, with semi-trucks, one party often owns the truck, or tractor,while another party owns the trailer. This split ownership createsoperational logistics problems for the delivery of power from the truckto the trailer. And trailers outnumber trucks by a factor of two orthree to one. Therefore, implementing truck to trailer power becomesimpractical, as the truck must be properly equipped to power therefrigeration system employed by the trailer. And there would need to besufficient numbers of trucks to power all trailers needing power.

Eutectic solid plate, or cold plate, refrigeration systems are anothertype of system employed by smaller delivery trucks. Cold plate systemsrely on heat transfer to large, solid plates, with the heat absorbed bythe cold plate cooling the surrounding air. Cold plate systems arecharged by shore power-driven (i.e. electric plug) vapor compressioncycle refrigeration systems. These systems are often used for trucksdesigned for local delivery and are characterized by much less precisetemperature control. These systems have many short-comings, includingtheir limited heat absorbance capacity, long recharge times for theeutectic plates, the limited temperature control features of the systemsand the excessively heavy weights of the plates. This has generallylimited the application of cold plates systems to smaller, localdelivery trucks.

Battery-powered trailer refrigeration units represent a third type ofsystem, though with more limited application than the truckalternator-powered TRU or cold plates. Battery-powered trailerrefrigeration units could be charged by shore power and many othermeans, including power provided by the truck APU. While these systemsenable diesel-free operation over the road, their initial cost isprohibitively expensive, they are impractically heavy to use for largerefrigerated trailer systems, and battery replacement cost further limittheir economic feasibility.

Large refrigerated containers, such as sea containers, generally utilizeVCC refrigeration units that are powered by high voltage electricitysupplied by the vessel when aboard ships and can be powered from shorepower during transit at ports. Sea containers using electrically-poweredVCC place a particularly large current demand on the system's electricalgrid aboard ship or from shore power when the unit cycles. The seacontainer systems also require significant steady state power requiringoversized power networks or very complex systems to manage the number ofunits operating and the timing of the cycling.

The considerations described above highlight the economic importance ofdeveloping more efficient cooling systems. In addition to these economicfactors, regulatory restrictions will create additional incentives toadopt more efficient systems. Recent regulatory activity in the U.S.relating to the diesel engine on TRU units has resulted in additionaladministrative and economic burdens for fleets operating diesel-poweredTRU units. Specifically, the environmental protection agency (EPA) andthe Air Resources Board of California (CARB) have enacted legislationrequiring reporting and upgrading the diesel engines and or emissionafter treatment equipment used on trailer refrigeration units.California law, as adopted in the CARB/EPA tier IV requirements of 2013,requires the business entities that arrange, hire, contract for, ordispatch TRU-equipped trucks, trailers, shipping containers, or railcarsfor transport of perishable goods on California highways and railways torequire the motor carriers to dispatch only TRUs that comply with theTRU Regulation. This legislation, in addition to the direct operationalfuel costs and indirect emission and noise impacts, provide significantincentives for the elimination of the diesel engine from the TRU.

Given the number of short-comings of the systems currently in operation,including the reliance of many systems on diesel power, the coupling ofthe trailer to the truck for power generation, and the high weight ofsome systems, there exists a strong and well-defined need for moreefficient cooling systems for the transport of perishable or temperaturesensitive goods in large trailers or containers. The present inventionprovides systems to meet these important needs as detailed in thefollowing disclosure.

SUMMARY OF INVENTION

The present invention provides a hybrid refrigeration and thermal energystorage system that enables the elimination of the diesel engine orauxiliary power unit (APU) from a TRU or other refrigeration unit in arefrigerated trailer, boxcar or other cooled air transport space. Thehybrid refrigeration and thermal energy storage system provides therequired discharge of refrigerated air for cooling of cargo orpassengers in large compartments. The system can be employed in a largecompartment, such as the trailer of a semi-truck, without the need for adedicated TRU diesel engine or other APU. The system can directly powera conventional VCC unit, such as an electric only TRU with high voltage,over the road to cool the refrigerated space. The system cansimultaneously power the VCC unit and charge a battery energy storage(BES) and/or thermal energy storage (TES) systems over the road. Thepresent invention also as provides cooling capability when the vehicleis stationary or parked using its TES and BES sub-system. For extendedperiods when the vehicle is not in motion, plug-in grid power providesthe power for VCC cooling and can also provide TES/BES charging.

While TESS and BESS systems provide the potential to eliminate thediesel engine from the TRU, the present invention in the form of hybridrefrigeration thermal storage or hybrid thermal storage system (HTESS)is particularly advantageous as it provides capability to minimize thesize of the TESS and BESS systems, minimize or eliminate the grid powerplug in requirement and at the same time avoids the cost, weight,emission, and regulatory impacts of the diesel APU.

The present invention employs a unique combination of components in asystem that derives power from the rotational motion of the wheels of avehicle and directly uses this high voltage energy for cooling acompartment, while simultaneously enabling the storage of energy fromthe motion in the form of chemical and thermal storage. The generatedpower may be produced in various forms. In one embodiment high voltage(i.e. over 60 volts) alternating current (AC) or high voltage directcurrent (DC) and low voltage (i.e. below 60 volts) DC are produced. Thedynamically-produced energy that is not used directly by theelectric-powered VCC unit to cool the space can be stored as chemicalenergy in the low voltage DC BESS and/or stored as thermal energycapacity produced through a secondary loop of the onboard VCC or TRUcooling system. The high voltage power electrical energy can be producedthrough a novel constant velocity output wheel/axle power generationsystem of the present invention, or by more conventional means such as ahybrid vehicle wheel motor or conventional direct drive gen-set.

In one embodiment, the high voltage AC or DC can be used to power anelectric-only TRU VCC or other refrigeration system to directly cool thecargo area, while at the same time providing power and refrigerationcapacity into the novel thermal energy storage TES and chemical batteryenergy storage BES systems of the present invention, Additionally, theprimary electromagnetic electricity generating system provided by thetrailer axle wheel rotation may be complemented by a supplementarysecondary power generating system that converts solar energy intoelectricity. This provides renewable electrical power to charge the BESSor to power the TESS electrical systems directly when the vehicle is notin motion and cannot generate primary power. When these primary andsecondary power elements are combined with chemical and thermal energystorage elements, the systems can be coupled together in such a way thata significant synergistic benefit is derived. More simply put, both theprimary and secondary electricity generators, as well as VCCrefrigeration, TESS, and BESS, work together to produce a sum ofdirectly available electrical power and refrigeration capacity that maybe more advantageously utilized than the systems considered on anindividual and separate basis. The inclusion of the primary andsecondary electrical power systems facilitate significant reductions inthe thermal energy storage (TES) system and the chemical or batteryenergy storage (BES) system size, weight, and cost. Further, theinclusion of the primary and secondary power systems integrated withonboard VCC, BESS and TESS reduces, and in most transport use cases caneliminate, the need for grid based charging of the BESS and TESSsystems. For example, trailers in continuous duty would remain thermallyand electrically charged or could be quickly restored to full charge onthe road without plugging in to the grid. This over-the-road chargingcapability for the TESS and BESS is especially effective forrefrigerated transport logistics, where vehicle wait time can be limitedand where providing multiple grid power points is operationallyprohibitive or expensive.

As discussed above, the present invention provides significantsynergistic benefits through the application of the primary wheel oraxle power to directly power the electric VCC while in motion. Due tothe novel combination of components and supply of power, and itsavailability over-the-road, the TES and BES system size and weight canbe minimized and the diesel APU engine and fuel tank can be eliminatedfrom the TRU. Eliminating the diesel APU reduces weight and the need fordiesel APU emissions compliance reporting and regulated engine andengine emission system upgrades. Since the primary electric power systemsupports the use of conventional or other electric-only TRU VCC systemswhile in motion, the BES and TES can be sized to support only therefrigeration and electrical power needs of the transport refrigerationvehicle when the vehicle is not in motion or not plugged into the grid.The HTESS therefore minimizes the TESS and BESS size and eliminates thediesel APU engine and fuel tank to facilitate reduced weight and spaceenvelope, which results in higher fuel and freight efficiently for thetrailer system. Further, with the use of secondary solar power, the BESsystem size, weight and cost can be further minimized and energyefficiency improved through the use of renewable power.

In addition to the weight and package envelope reductions achievedthrough eliminating the diesel TRU APU engine, significant cost andadministrative advantages to refrigerated trailer operators are alsorealized. For example the HTESS TRU would no longer be subject toEnvironmental Protection Agency and California Air Resources Boardstipulated upgrades and reporting on diesel engines providing asignificant operational cost advantage over and beyond the diesel fuelsavings.

An additional synergistic advantage of the HRTESS system is the use ofthe available ABS brake communication or other signal inputs to identifyconditions for charging the TESS and BESS systems, which, much like ahybrid car, can recover otherwise wasted deceleration energy. Unlikemany battery hybrid systems, however, the HRTESS system can absorb highlevels of energy and power during deceleration or braking events. Overthe road, the thermal and chemical energy TESS and BESS can becontrolled to be fully-charged quickly for maximum coverage of idleperiods, or can be partially discharged and recharged over the road totake advantage as much as possible of the recovered vehicle decelerationenergy events. The discharge/recharge feature, while broadly applicable,can be especially useful for city transit busses which start and stopfrequently and even on hybrid electric busses may have limits on whatelectrical energy is recoverable during braking events due to limitedbattery capability to absorb the power quickly. The HTESS, even whenapplied to a non-hybrid bus for air conditioning can provide significantenergy recovery fuel savings as air conditioning loads can contribute toover 40% of hot weather fuel consumption. For critical refrigerationcargo, on the other hand, it may be desirable to maintain TESS and BESSfully-charged and take less advantage of energy recovery decelerationevents. In this scenario, the HTESS still provides significant fuelsavings because the incremental power increase needed from the truckengine to power an active HTESS primary power generation system is avery small load compared to the amount of power used to pull the loadedtrailer. Accordingly, the incremental increase in power needed from thetruck engine does not significantly impact its overall fuel consumption.

The TES system can charge quickly and provide multi-temperature coolingover the road without diesel APU noise and undesirable emissions. Thesystem operates at a reduced weight and cost compared to eutectic orbattery-only powered systems. The HTESS is not applicable to seagoingvessels in the same manner as road vehicles, however, in sea-goingapplications, a TES system according to aspects of the invention canextend the window in which sea-container refrigeration systems must beoperated with high-power VCC, thereby reducing the complexity of thecontrol systems, the peak power demand and the ultimate capacity of thepower supply system.

In further aspects, the present invention provides defrost systems witha novel, reverse-flow approach to minimize defrost energy whilemaintaining the cooling power delivered to the refrigerated space.

In a first aspect the present invention provides an integrated powergeneration, energy storage and refrigeration system. The integratedpower generation, energy storage and refrigeration system of the firstaspect includes a plurality of wheels, an axle affixed to at least oneof the plurality of wheels, an electric power generator that convertsthe rotational motion of the wheels into electric power, a thermalenergy storage unit. The thermal energy storage units has a heatexchanging fluid and a cooling unit to thermally charge the fluid. Thecooling unit is powered by the electric power generator.

The integrated system according to the first aspect can include aconstant output velocity device coupled at a first end to the axle andat a second end to the electric power generator. The constant outputvelocity device maintains the rotational power delivered to thegenerator within a prescribed rotational velocity range according to theefficient operating parameters of the generator. In other words, thegenerator may operate most effectively within a range of revolutions perminute or some similar parameter. The constant output device adjusts therotational speed delivered to the generator accordingly to meet thedemands of the generator. In certain embodiments the constant outputvelocity device can be a constant velocity continuously variabletransmission or a hydraulic pump and motor set. In alternativeembodiments, of the integrated system the electric power generator canbe a wheel motor generator.

The integrated system according to the first aspect can include a DC-DCconverter or an AC-DC inverter and a TES low power battery electricsystem. The converter or inverter facilitates the powering of TEScomponents and charging of the TES low power battery electric system bythe electric power generator. The TES low power battery electric systemis implemented to supply auxiliary power to components of the thermalenergy storage unit or an auxiliary low voltage cooling unit to chargethe TESS.

In certain embodiments the system can include an electronic control unitadapted to regulate the thermal energy storage unit, a temperaturesensor adapted to monitor the temperature of the heat exchanging fluid,a fan adapted to circulate air in a cargo or passenger space, one ormore pumps adapted to circulate the heat exchanging fluid and divertersadapted to route the flow of the heat exchanging fluid through a heatexchanger. These additional components can be powered by the TES lowpower battery electric system.

The integrated system according to the first aspect can also include asolar energy collecting unit. The solar energy collecting unit can beused to supply auxiliary power to the thermal energy storage unit or tosupply auxiliary power to an auxiliary low voltage cooling unitconfigured to charge the TESS or cool a conditioned space. Additionally,the TES low power battery electric system can be adapted to selectivelycharged by the solar energy collecting unit and the electric powergenerator, depending upon the status of the trailer or other mobileunit. For example, if the trailer was stationary charging by the solarenergy collecting unit would be selected, while in motion might favorcharging by the electric power generator. The TES low power batteryelectric system is implemented to supply auxiliary power to componentsof the thermal energy storage unit. The integrated power system caninclude a controller module adapted to manage the supply of powerbetween to the solar energy collecting unit and the electric powergenerator. Similarly, the integrated power generation, energy storageand refrigeration system can include a control logic and control unit tomanage state of charge of the TES or BES systems based on operationalparameters of the vehicle provided from an OBD or general CAN link orother available vehicle data device. Using such a controller with thevehicle data, deceleration energy use can be managed to address chargingof the TESS over the road to maintain a base state of charge such thatthe thermal energy storage unit is charged during deceleration eventsand partially discharged during normal road use to manage energyconservation.

The integrated power system according to the first aspect can alsoinclude resistive heating coils powered by the electric power generator.The heating coils can be implemented to heat an enclosed cargo orpassenger space or to defrost the thermal energy storage unit.

In still further embodiments, the integrated power system according tothe first aspect can also include a high temperature battery (HTB), anHTB heat exchanger, and a fan. The fan can be employed to circulate airfrom a cargo or passenger space across the HTB heat exchanger. Inadvantageous embodiments the high temperature battery is a sodium nickelchloride battery.

The cooling unit of the thermal energy storage unit according to thefirst aspect can be a vapor compression cycle (VCC) system. Similarly,the heat exchanging fluid of the thermal energy storage unit accordingto the first aspect can be a phase change material (PCM).

In certain embodiments, the thermal energy storage unit of theintegrated power system according to the first aspect can include aphase change material (PCM) reservoir containing a phase changematerial, a working fluid (WF) and a working fluid-to-PCM heatexchanger, a cooling unit-to-WF heat exchanger adapted to remove heatfrom the working fluid, and a PCM-to-target heat exchanger in fluidcommunication with the PCM reservoir. The working fluid-to-PCM heatexchanger is in contact with the PCM and the WF, and the PCM is the“heat exchanging fluid.” The cooling system-to-WF heat exchanger is influid communication with the PCM reservoir, and the WF circulatesbetween the PCM reservoir and the cooling system-to-WF heat exchangerforming a charging loop. Similarly, the PCM circulates between the PCMreservoir and the PCM-to-air heat exchanger and forms a dischargingloop.

In alternative embodiments, the thermal energy storage unit of theintegrated power system according to the first aspect can include aphase change material (PCM) reservoir containing a phase changematerial, a cooling unit-to-PCM heat exchanger adapted to remove heatfrom the PCM and a PCM-to-target heat exchanger in fluid communicationwith the PCM reservoir. The PCM is the “heat exchanging fluid.” Thecooling system-to-PCM heat exchanger is in fluid communication with thePCM reservoir. The PCM circulates between the PCM reservoir and thecooling system-to-PCM heat exchanger to form a charging loop. Similarly,the PCM circulates between the PCM reservoir and the PCM-to-air heatexchanger to form a discharging loop. Thus, these embodiments do not usea separate “working fluid” to charge the PCM.

In a second aspect the present invention provides a second integratedpower generation, energy storage and refrigeration system. The systemaccording to the second aspect includes a chassis, a wheel rotatablycoupled to the chassis and adapted for contact with a road surface, aconstant output velocity unit in rotational communication with thewheel, an electric power generator in rotational communication with theconstant output speed drive unit and a thermal energy storage (TES) unithaving a heat exchanging fluid and a cooling unit to charge the fluid,the cooling unit powered by the electric power generator. The constantoutput velocity unit supplies rotational power to the electric powergenerator within a prescribed range of rotational velocity and thegenerator converts the rotational motion of the wheels into electricpower.

The TES system of the integrated power generation, energy storage andrefrigeration system according to the second aspect can include a phasechange material (PCM) reservoir containing a phase change material (asthe heat exchanging fluid), a working fluid (WF) and a workingfluid-to-PCM heat exchanger, a PCM-to-target heat exchanger in fluidcommunication with the PCM reservoir, a first pump to circulate the PCMbetween the PCM reservoir and the PCM-to-target heat exchanger, a vaporcompression cycle (VCC) system, a VCC-to-WF heat exchanger adapted toremove heat from the working fluid and in fluid communication with thePCM reservoir, a second pump to circulate the WF between the PCMreservoir and the VCC-to-WF heat exchanger, and a state of chargedetection system to monitor the charge of the PCM. The workingfluid-to-PCM heat exchanger of the PCM reservoir is in contact with thePCM and the WF. The PCM circulates between the PCM reservoir and thePCM-to-air heat exchanger, which enables cooling of a conditioned spaceas the PCM absorbs heat form the surroundings across the PCM reservoir.Similarly, the WF circulates between the PCM reservoir and the coolingsystem-to-WF heat exchanger, allowing the working fluid to absorb heatform the PCM. The chassis can be a trailer chassis adapted to be pulledby a tractor. The heat exchanging fluid can be a phase change material(PCM). Similarly, the cooling unit of the thermal energy storage unitcan be a vapor compression cycle (VCC) system.

The integrated power generation, energy storage and refrigeration systemaccording to the second aspect can include a solar energy collectingunit adapted to supply auxiliary power to the thermal energy storageunit or to supply auxiliary power to an auxiliary low voltage coolingunit configured to charge the TESS or provide cooling to a conditionedspace. In an advantageous embodiment, the integrated power systemaccording to the second aspect can include a TES low power batteryelectric system adapted to be selectively charged by the solar energycollecting unit and the electric power generator. The TES low powerbattery electric system is implemented to supply auxiliary power tocomponents of the thermal energy storage unit.

The integrated power generation, energy storage and refrigeration systemaccording to the second aspect can further include an electronic controlunit adapted to regulate the thermal energy storage unit, a temperaturesensor adapted to monitor the temperature of the heat exchanging fluid,a fan adapted to circulate air in a cargo space, one or more pumpsadapted to circulate the heat exchanging fluid and/or diverters adaptedto route the flow of the heat exchanging fluid through a heat exchanger.These components can be powered by the TES low power battery electricsystem.

The integrated power system according to the second aspect can alsoinclude resistive heating coils powered by the electric power generator.The heating coils can be implemented to heat an enclosed cargo orpassenger space or to defrost the thermal energy storage unit.

In a third aspect the present invention provides a hybrid-poweredregenerative mobile thermal energy storage system. The hybrid-poweredregenerative mobile thermal energy storage system includes a chassis, awheel rotatably coupled to the chassis and a thermal energy storageunit. The wheel is adapted for contact with a road surface and the wheelhas a wheel motor generator for the conversion of rotational mechanicalenergy of the wheel into electrical power. The thermal energy storageunit has a heat exchanging fluid and a cooling unit to charge the fluid.The cooling unit is powered by the wheel motor generator. The coolingunit can be a vapor compression cycle (VCC) system.

In certain embodiments the hybrid-powered regenerative mobile thermalenergy storage system according to the third aspect can include a DC-DCconverter or an AC-DC inverter and a TES low power battery electricsystem. The converter or inverter is adapted to facilitate powering ofTES components and charging of the TES low power battery electric systemby the wheel motor generator. The TES low power battery electric systemis adapted to supply auxiliary power to components of the thermal energystorage unit or an auxiliary low voltage cooling unit to charge theTESS.

In further embodiments the hybrid-powered regenerative mobile thermalenergy storage system according to the third aspect can include anelectronic control unit adapted to regulate the thermal energy storageunit, a temperature sensor adapted to monitor the temperature of theheat exchanging fluid, a fan adapted to circulate air in a cargo space,one or more pumps adapted to circulate the heat exchanging fluid and/ordiverters adapted to route the flow of the heat exchanging fluid througha heat exchanger. These components can be powered by the TES low powerbattery electric system.

In still further embodiments the thermal energy storage unit of thehybrid-powered regenerative mobile thermal energy storage systemaccording to the third aspect can include a phase change material (PCM)reservoir (containing a phase change material as the “heat exchangingfluid”, a working fluid (WF) and a working fluid-to-PCM heat exchanger),a cooling unit-to-WF heat exchanger adapted to remove heat from theworking fluid, and a PCM-to-target heat exchanger in fluid communicationwith the PCM reservoir. The PCM circulates between the PCM reservoir andthe PCM-to-air heat exchanger forming a discharging loop. The workingfluid-to-PCM heat exchanger of the PCM reservoir is in contact with thePCM and the WF. The cooling system-to-WF heat exchanger is in fluidcommunication with the PCM reservoir, and the WF circulates between thePCM reservoir and the cooling system-to-WF heat exchanger forming acharging loop.

In a fourth aspect the present invention provides a secondhybrid-powered regenerative mobile thermal energy storage system. Thehybrid-powered regenerative mobile thermal energy storage systemaccording to the second aspect includes a wheel adapted for contact witha road surface, an axle affixed to the wheel, a constant output velocityunit coupled to the axle, an electric power generator coupled to theconstant output velocity unit that converts the rotational motion of thewheel into electric power, and a thermal energy storage unit having aheat exchanging fluid and a cooling unit to charge the fluid. Thecooling unit can be powered by the electric power generator. In certainembodiments, the constant output velocity mechanical device is aconstant velocity continuously variable transmission or a hydraulic pumpand motor set.

In a fifth aspect the present invention provides an integrated powergeneration, energy storage and temperature control. The system accordingto the fifth aspect includes a chassis, a wheel rotatably coupled to thechassis and adapted for contact with a road surface, a constant outputvelocity unit in rotational communication with the wheel, an electricpower generator in rotational communication with the constant outputvelocity unit, and a high temperature battery (HTB). The constant outputvelocity unit adjusts the rotational velocity delivered from the wheelto a prescribed rotational velocity range and supplies rotational powerto the electric power generator within a prescribed range of rotationalvelocity. The generator then converts the rotational motion of thewheels into electric power. The high temperature battery can be a sodiumnickel chloride battery.

In certain embodiments, the integrated power generation, energy storageand temperature control system according the fifth aspect can alsoinclude an HTB heat exchanger and a fan. The fan can be employed tocirculate air from a cargo or passenger space across the HTB heatexchanger. In still further embodiments of the fifth aspect a batteryheater can be included to warm up the HTB battery. Additionally, a HTBresistance heater adapted to heat a conditioned space can be included inembodiments of the fifth aspect.

In still further embodiments, the integrated power generation, energystorage and temperature control system according to the fifth aspect caninclude a thermal energy storage (TES) unit having a heat exchangingfluid and a cooling unit to charge the fluid. The cooling unit can bepowered by the electric power generator.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdrawings, descriptions and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference should be made tothe following detailed description, taken in connection with theaccompanying drawings, in which:

FIG. 1 is a schematic illustration of a mobile thermal energy storagesystem (TESS) according to one aspect of the invention.

FIG. 2 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS).

FIG. 3 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) according to one aspect of the invention wherehigh voltage AC power is provided by wheel/axle powered gen-set throughconstant output speed mechanical device.

FIG. 4 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) according to one aspect of the invention wherehigh voltage DC power is provided by wheel motor power.

FIG. 5 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) according to one aspect of the invention wherehybrid truck power is provided.

FIG. 6 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) according to one aspect of the invention wherehigh voltage AC/DC power is provided directly from the truck powertakeoff device (PTO) generator.

FIG. 7 is a schematic illustration of a mobile thermal energy storagesystem (HTESS) heating system options including DC electric, ACelectric, gas fired and a DC heater battery chemical heat.

FIG. 8 is a schematic illustration of a novel mobile thermal energystorage system (HTESS) heating option combining chemical storage andthermal storage.

FIG. 9 is a schematic illustration of the discharging loop for coolingan enclosure of the mobile thermal energy storage system shown inFIG. 1. The discharging loop employs a phase change material to cool thespace confined by an enclosure transport cargo or othertemperature-sensitive payloads.

FIG. 10 is a schematic illustration of the charging loop of the mobilethermal energy storage system shown in FIG. 1. The charging looprecharges the phase change material of the discharging loop.

FIG. 11 is a schematic illustration of an alternative embodiment of amobile thermal energy storage system according to another aspect of theinvention. The thermal energy storage system of FIG. 11 employsoff-board charging of the working fluid in the charging loop using anexternal TESS-VCC loop as opposed to the on-board charging of theworking fluid using an internal TESS-VCC loop as illustrated in FIG. 1.

FIG. 12 is a schematic illustration of an alternative embodiment of amobile thermal energy storage system according to another aspect of theinvention. The thermal energy storage system of FIG. 12 employs anevaporator external to the TES system to allow parallel or back-upcooling of cargo. The schematic of FIG. 12 illustrates charging of themobile TESS system with VCC cooling provided to the cargo in parallel.

FIG. 13 is a schematic illustration of an alternative embodiment of amobile thermal energy storage system according to another aspect of theinvention. FIG. 13 illustrates the discharging, cargo cooling, portionof the mobile TES system with VCC supplemental cooling using an externalevaporator.

FIG. 14 is a schematic illustration of the subsystem to manage defrostvia flow reversal and flow control. FIG. 14 shows the standard flowthrough the discharge loop under the control of the defrost system. Inparticular, the flow through the reversing valve and the heat exchangerare routed as in standard operating conditions of the discharge loop.

FIG. 15 is a schematic illustration of the subsystem to manage defrostvia flow reversal and flow control as shown in FIG. 14. FIG. 15 showsthe defrost flow through the discharge loop under the control of thedefrost system when frost has been detected. In particular, the flowthrough the reversing valve and the heat exchanger are routed as indefrost operating conditions of the discharge loop.

FIG. 16 is a schematic illustration of the subsystem to manage defrostvia flow reversal and flow control as shown in FIG. 15. FIG. 16 adds theelement of a supplemental electric heat defrost system to the systemshown in FIG. 15.

FIG. 17 is a flowchart of a simplified control algorithm for on-boardTESS Eutectic Slurry Phase Change Material (ESPCM) charging.

FIG. 18 is a flowchart of a simplified control algorithm for theprevention of solid ice formation during on-board TESS ESPCM charging.

FIG. 19 is a flowchart of a simplified control algorithm for off-boardTESS ESPCM charging.

FIG. 20 is a flowchart of a simplified control algorithm for theprevention of solid ice formation during off-board TESS ESPCM charging.

FIG. 21 is a flowchart of a simplified control algorithm for TESScooling.

FIG. 22 is a flowchart of a simplified control algorithm for TESS frostprevention during on-board TESS cooling.

FIG. 23 is a flowchart of a simplified control algorithm for deliveringcommands to fans, ESPCM pumps, and defrost heaters during on-board TESScooling.

FIG. 24 illustrates a TES system installed at the front of arefrigerated trailer.

FIG. 25 illustrates a TES system installed at the center of amulti-temperature application, where it is cooling the rear portion of atrailer.

FIG. 26 illustrates a TES system installed at the front of arefrigerated trailer.

FIG. 27 is a schematic illustration of a slurry generator system.

FIG. 28 is a schematic illustration of a PCM/working fluid heatexchanger.

FIG. 29 is a schematic illustration of a helical heat exchanger fin onthe tube of a heat exchanger.

FIG. 30 is a schematic illustration of a TESS with a system toincrease/saturate the dissolved gas level (e.g. CO₂) in the ESPCMslurry.

FIG. 31 is a schematic illustration of a TESS with a mechanical scrapingslurry system.

FIG. 32 is a schematic illustration of a slurry generator using directVCC cooling.

FIG. 33 is a schematic illustration of a slurry generator using directVCC cooling.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a hybrid-powered thermal energy storagesystem (HTESS) that enables the discharge of refrigerated air forcooling cargo or passengers in large compartments, such as the trailerof a semi-truck a transit bus or a rail-container, for typical shiftservice life periods and indefinitely while in motion over the road orwhile plugged into shore power. The HTESS system is able to providerefrigeration without the use of a conventional TRU diesel APU engineduring the entire service use, or the entire time a 53-foot refrigeratedthe truck or transit bus is traveling over the road. Additionally, HTESScan provide cooling without operating the VCC system or the truck/busengine for several hours while the trailer or bus is parked or is idlingin traffic.

The HTES system can charge quickly via shore power or trailer wheel/axlemotor power over the road and provide multi-temperature cooling over theroad and while stationary, thereby eliminating the diesel APU andassociated undesirable noise and emissions. The system operates at a netzero or at a reduced weight when compared to conventional TRU systemsand at a substantially lower weight than current eutectic orbattery-only powered systems. In sea-going applications, only the TESsystem is applicable and according to aspects of the invention canextend the window in which sea-container refrigeration systems must beoperated with high-power VCC, thereby reducing the complexity of thecontrol systems, the peak power demand and the ultimate capacity of thepower supply system.

In further aspects, the present invention provides constant speedmechanical output power to a high-power onboard alternating current (AC)gen-set through a constant output velocity mechanical device (CVMD) suchas a constant velocity continuously variable transmission (CVCVT), or ahydraulic pump and motor set powered by the trailer or bus axles. Thisis advantageous in that high power AC gensets employed to power VCCsystems are very efficient means to power electric motor driven VCCsystems and are most efficient operating at a specific operating speed.While it can be seen that the HTESS CVCVT design could be used without aTESS in a battery-only trailer application, the battery-only applicationsuffers from higher initial cost and higher battery replacementmaintenance costs. In another advantageous embodiment, high power directcurrent is provided by a hybrid wheel motor as developed originally forpassenger cars. The advantage of applying the wheel motor/wheel motorgenerator developed for hybrid cars and light trucks to the TESS systemis that the controls and safety systems for managing power are designedand verified.

In still further aspects, the present invention provides low-powercharging through the aforementioned high-power sources converted orinverted to low-power to charge the TESS low power battery electricsystem (BES) and to power its low-power pumps and fans over the road. Infurther aspects, a solar power unit or low power APU provides low powercharging and TES system power during idle periods on the road or whileparked staging.

In yet further aspects, the present invention provides for novel heatingof the conditioned space while the high-power systems are not availablethrough thermo-chemical battery/dc electric heating or, in anotherembodiment, more conventional heating methods, such as propane gas orhigh power electric-only heat. Over the road the HTESS AC or DC powerfacilitates conventional high-powered heating methods, such as AC or DChigh power resistive heating coils.

In another aspect, the HTESS can also provide non-HPS (high powersystem) heating via more conventional means such as direct gas (lpg,gasoline, diesel) heating or thermal storage of electrical or otherwisegenerated heat in the PCM reservoir.

The present invention provides systems and methods for a Hybrid ThermalEnergy Storage System (“HTES system” or “HTESS”) that is characterizedby rapid charging of the TESS and then providing portable, self-powered,multi-temperature refrigeration control for large, mobile transportenclosures without the use of diesel APU. The TES system of theinvention is capable of providing efficient refrigeration control acrossa wide range of temperatures including the temperature range of 40° F.to −20° F., as required in many important refrigerated cargoapplications and also has application for passengers or other cooling inlarge compartments, such transit bus or a sea-container. HTESS providescooling confidently for typical shift service life periods andindefinitely while in motion over the road or while plugged into shorepower. The HTES system is able to provide refrigeration withoutoperating a conventional TRU diesel APU engine during the entire portionof the period of the typical range of time that a 53-foot refrigeratedthe truck or transit bus is traveling over the road, allowing theelimination of the diesel engine and fuel tanks from the TRU.Additionally, HTESS can provide cooling without operating the VCC systemfor several hours while the trailer or bus is parked or is idling intraffic. To accomplish this, the HTESS is thermally charged via a VCCwhich is powered by high-voltage shorepower or over the road with anovel constant velocity mechanical device (CVMD) such as a constantvelocity continuously variable transmission or a hydraulic pump andhydraulic motor set driven by the truck through the trailer wheels oraxle and regulated to provide constant speed to a alternating currentgen-set. The HTESS is thermally charged by shore power or the CVMD. TheCVMD of the HTESS provides power to the VCC motor for VCC direct loadcooling over the road with the AC genset power. The CVMD and VCC alsothermally charges the TESS to maintain maximum TESS capacity. Thelow-power TESS battery system is also charged by the CVMD and AC gensetthrough power supplies, which step down the voltage and convert AC to DCPower. In an advantageous embodiment this DC power is configured to becompatible with solar power units such that while parked or in motion,solar panels on the top of the truck can augment charging of the TESSBES system and to provide power for TESS functions such as fans andpumps directly. Solar or other battery charge controllers are used tomanage the interface power needs and charging of TESS pump/fan loads andBES system charging.

In an exemplary configuration the HTES system employs a high powersource (HPS) from both high voltage shorepower (SPHPS) and over the roadhigh power (OTRHPS) through the application of a novel on board constantvelocity mechanical device (CVMD) such as a constant velocitycontinuously variable transmission (CVCVT) or a hydraulic pump andhydraulic motor set. The CVMD is powered by energy derived from thetruck engine through the trailer wheels or axle and speed regulated toprovide constant speed for efficient power from typical OTRHPSalternating current (AC) gen-sets. The OTRHPS or shorepower high powersource (SPHPS) provides direct power to the HTESS onboard VCC motor,fans, heaters, and controls to thermally and electrically charge theTESS system and/or provide direct heating/cooling to the conditionedspace. While parked and plugged into SPHPS, or moving over the roadusing (OTRHPS), (HPS) is available to power the high power VCCfunctions. The HTESS system also employs a low power system, forproviding TESS electrical needs and recharging the TESS battery electricsystem (BES). The TESS BES system is recharged over the road throughOTRHPS or while plugged in using SPHPS through power supply conversionof high voltage AC to the appropriate level of low power DC.Additionally, the TESS battery energy storage (BES) system can berecharged or TESS low power functions directly powered through solarpanels on the top of the trailer or alternately, if desired, via a smalllow power APU.

The HTESS has an advantage over the TESS system due to the OTRHPSavailability to provide a large share of the cooling needs such that theHTESS thermal storage size and BES size can be sized only for thevehicle-idle portions of the duty cycle, such as staging or idling intraffic. Additionally, with the HTESS the TESS thermal charging need notbe fully completed using shore power as the OTRHPS can thermally andelectrically charge the TESS over the road.

The HTESS can further employ overhead solar panels and solar powercontrollers (ECU) to power the TESS and continuously charge the BESsystem allowing further reduction in BES size. For example, the systemcan employ a “solar controller/battery charger” which “thinks” theinverted, low-voltage (24 volts) from the OTRHPS is a solar panel. Thisis advantageous because photovoltaic (PV) solar panel system's“controller/battery chargers” have been developed and optimized tomanage the direct use of the power and the battery charging/storage willlikely have a different optimization based on the battery type. The PVpanels put out 24 volts generally. For the TESS, the solar-provided 24volts can be used while parked and driving to run the TESS fans and/orpumps directly and to charge the batteries of the TES system.Additionally, the over-the-road system can also be used do this todirect drive the TESS system as needed (running pumps to charge) or withspecial controls as described herein to manage use of decelerationenergy to charge.

The present HTESS invention further proposes the use of an a novelheating system to provide heating when HPS is not immediately available,such as when idling or staging in cold weather and not plugged in. Thenovel HTESS heating system uses a combined electrical and chemicalheating system or a battery-based combined heat and power system. Incold weather when non-HPS heating is anticipated, the HTESS employs hightemperature batteries (HTB) (such as sodium nickel chloride batteries(Zebra)) in a high temperature battery heating system (HTBHS) to provideheating. When use is anticipated, such as ambient temperatures droppingbelow a set point, electric heater driven by the OTRHPS, the SPHPS orthe HTB itself is commanded by the ECU to preheat or maintain heat ofthe HTESS (HTB) cooling reservoir of the HTBHS to achieve operatingtemperature of the battery (which is otherwise inert as it beginselectrical operation at 300° C.). During non-HPS operating periods, theHTB provides direct air heating to the conditioned space through a DCresistance heater and its own exothermic reaction to the HTB coolingreservoir and heat exchanger. The HTB, stores electrical and heat energyat a significantly higher energy density (KJ/KG), (KJ/m3) than any known“hot PCM” material. It has several key advantages in addition to theenergy storage density. Unless preheated, it is inert and retains acharge for very long periods of time, so for example, during hotseasonal periods of time when the HTB heating energy is not required toheat the conditioned space, the HTB remains off. During heating season,the HTB takes several days to cool off and can maintain its owntemperature reducing the need for active charging. In an advantageousembodiment, a zebra HTB converts electrical to heat energy at 100%efficiency and although electrical discharge efficiencies are in the 75%range, when used as a combined heat and power device, an HTB can providewell over 85% efficiency.

The operation of large cargo/shipping containers, whether they aretrucks, trains, planes, buses, ships, etc., can be divided into twophases: (1) time spent actually in transit and (2) time spent with thecargo, goods or passengers where the vehicle is not in transit but thecargo is nevertheless under the control of the vehicle, such as a shipin dock or a truck at a truck stop. During these non-transit times,external power sources, or shorepower high power source (SPHPS), willoften be available that can be used to re-charge the systems, and at afraction of the cost of using the on-board power systems. Thesenon-transit power sources are referred to herein as “shorepower,” whichincludes the traditional definition of the provision of shoresideelectrical power to a ship at berth while its main and auxiliary enginesare turned off, but applies more generally to the provision of power byan external power source to recharge the cooling system of the vehicle.

While these shorepower high power source (SPHPS) occasions often arepresented in trucking and other operations, making this a requirement,for example for a diesel-free TESS system, does present a significantlogistical constraint for the use of TESS in various applications. Forexample, recharge time may be prohibitively short, or travel time maybecome too long for TESS to be practical without over the road highpower system (OTRHPS) availability for refrigeration and recharging TheHybrid TESS (HTESS) overcomes the need for the diesel backup TRU tocover all conditions by providing a practical over the road high powersource (OTRHPS) to power VCC, heating functions, and fully charge theTESS for occasions when shorepower time will not be adequate. The systemfurther provides a low power solar or other system to extend the TESSelectrical system operating period when not powered by a high powersystem (HPS), such as shorepower or OTRHPS. With the OTRHPS and solarpower of the HTESS, the TESS system and its associated battery systemmay be also downsized significantly, making it more attractive forsignificantly broader customers in markets of mobile transportationheating/refrigeration and climate control. With the displacement of thediesel engine and its associated 60-120 gallon tank, the HTESS alsooffers a net zero or net negative (lower weight) than a conventional TRUunit.

Turning to the figures, FIG. 1 provides an overview of an exemplary TESmobile refrigeration system 10. The TES system 10 includes a dischargingloop 12 and a charging loop 13. The discharging loop 12 and the chargingloop 13 share an insulated ESPCM reservoir 20, containing an ESPCM 22,which is stored as a slurry in the ESPCM reservoir 20. By “ice slurry”or “slurry” it is meant a mixture of small ice particles and carrierliquid. Ideally, the slurry is a homogenous mixture of small iceparticles and carrier liquid dispersed throughout the reservoir, but inpractice the mixture is often stratified with the ice tending towardsthe top of the reservoir. The liquid can be either pure freshwater or abinary solution consisting of water and a freezing point depressant.Sodium chloride, ethanol, ethylene glycol and propylene glycol are fourmost commonly used freezing point depressants in industry. Thegeneration and application of ice slurries is discussed in more detailby Kauffled, M. et al., Int J Refrig. 2010 Dec. 1; 33(8): 1491-1505. TheESPCM will be in a semi-liquid state due to a temperature at roughly thetransition point between solid and liquid. The discharging loop 12 usesthe ESPCM 22 to absorb heat from the surroundings thereby allowing theESPCM to effect the cooling of a cargo during shipment, while thecharging loop 13 absorbs heat from the ESPCM 22, usually while thesystem is plugged into shorepower, or otherwise not in transit, tofacilitate the further use of the ESPCM 22 in the discharging loop 12.The ESPCM 22 in the reservoir 20 surrounds, and is in contact with, anESPCM slurry generator 30, also referred to as a working fluidreservoir, and contains a working fluid 32. Facilitating heat transferfrom the WF to the ESPCM, and consequent charging of the ESPCM withinthe ESPCM reservoir is a WF-to-ESCPM heat exchanger, also referred to asthe PCM/WF heat exchanger, which maintains separation of the PCM and WFand increases the surface area over which heat exchange between the twocan occur.

The ESPCM reservoir 20 forms a starting point of reference for movingthrough the discharging loop 12. The ESPCM reservoir 20 is in fluidcommunication with an ESPCM fluid pump 40, a bypass valve 50, areversing valve 60, and an ESPCM/AIR heat exchanger 70. A fan system 80and a defrost system 90 are located in proximity to the ESPCM/AIR heatexchanger 70. The components of the discharging loop are powered by abattery electric system 120 or other appropriate source of power. Thedetails of the discharging loop 12 are described in more detail withreference to FIG. 9, below.

The ESPCM slurry generator 30, forms a starting point of reference forthe charging loop 13 and the generator in fluid communication with areversing valve 62, a VCC-to-working fluid heat exchanger 72, aconventional on-board VCC system 132 and a working fluid charging pump42. The VCC-to-working fluid heat exchanger 72 and the conventionalon-board VCC system 132 in combination form the TESS VCC loop 14. Poweris provided to the charging loop 13 by electrical shore power 142, orother suitable electrical source, such as via truck alternator power, asmall auxiliary power unit or through a wheel motor generator. Shorepower 142, also recharges the battery electric system 120 while the TESsystem 10 is in charging mode. The details of the charging loop 13 aredescribed in more detail with reference to FIG. 10, below.

Both the discharging loop 12 and the charging loop 13 are under thecontrol of an electronic control unit 100. Additionally, a state ofcharge detection module 110 monitors the temperature and/or pressure ofthe ESPCM 22 in the ESPCM reservoir 20 during both the charging mode andthe discharging mode.

FIG. 2 provides an overview of an exemplary HTESS mobile refrigerationsystem H1 which includes the TES system 10 (as shown for instance inFIG. 1). The Hybrid TES HTESS system H1 includes the TESS system 10, anover-the-road high-power system (OTRHPS) H2, a low-power system H3, aheating system H4, and a hybrid TESS controller H5. The over-the-roadhybrid system H2 is comprised of a trailer wheel/axle power take up H6,a mechanical constant output speed drive H7 and a three-phase high powerelectric gen set H8. High power over-the-road is generated in thisOTRHPS and can be directly used by the high power elements of the VCCsystem disclosed in the TESS 10. Additionally, while in motion over theroad, the high power from the OTRHPS H2 is converted to DC low power inthe low power system 113 by an AC-to-DC converter 1113 and used tocharge the battery energy storage system (BES) 120 of the TESS 10 ordirectly drive low power systems of the TESS 10 such as pumps 40 andfans 80. Also included in the low power system, is a low voltageindependent stationary power source 119, such as solar panels, which canbe used to power the low power TESS 10 functions or charge the BES 120of the TESS 10. A low power battery charger load controller 1110, suchas a solar battery charger load controller, is provided in the low powersystem 113 to manage the loads and the battery charging efficiently. Theheating system 114, uses high power OTRHPS power to power conventionalresistive heaters directly when traveling over the road and employs anovel high temperature battery (HTB) heating system to provide heatingpower while high power systems OTRHPS and shore power high power systemSPHPS are not available.

FIG. 3 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) where high voltage AC power is provided bywheel/axle powered gen-set through a mechanical constant output speedmechanical device 160. The mechanical constant output speed mechanicaldevice 160 provides high voltage AC 162 to an AC/DC converter 164, an ACelectric heater 94, an AC electric motor 166, and a charge pump 40. TheAC/DC converter 164 can then supply power to the battery charge/loadcontroller 122, which in turn provides power to the battery electricsystem 120, the fan 80 and the discharge pump 42 of the TESS system 10.The battery charge/load controller 122 can also supply power to a lowvoltage VCC system 134, which can be used to provide back-up cooling toboth the TESS system 10 and the conditioned space (i.e. the spacecontaining the cargo). The AC electric heater 94 provides heat to theconditioned space and provides electric defrosting for the TESS system10, including the TESS system's heat exchangers. The AC electric motor166, powers the primary VCC system 132, which is used to providescooling for the TESS system 10 and can be used to directly cool theconditioned space when needed. The system of FIG. 3 also includes a CANBus data module 102 that interfaces with the HTESS electronic controlunit 100. The identification of decelerations or “energy recovery mode”events can be accomplished using CAN Bus data, that data includingvehicle speed, acceleration/deceleration events, and brake applications.The HTESS ECU 100 can use the data to switch between “energy recoverymode” from deceleration events and energy supply from the mechanicalconstant output speed mechanical device 160.

The system shown in FIG. 3 also includes solar panels 144 as anauxiliary power unit, supplying auxiliary power to the batterycharge/load controller 122, which in turn can charge the batteryelectric system 120 and enable the powering of critical systemsincluding the fan 80 and the discharge pump 42 of the TESS system 10,and the low voltage VCC system 134. At the heart of the system shown inFIG. 3 is the thermal storage device 20 (ESPCM reservoir) of the TESSsystem 10, which provides cooling for the conditioned space.

FIG. 4 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) where high voltage DC power is provided by ahybrid DC wheel motor generator 170. The hybrid DC wheel motor generator170 provides high voltage DC 172 to a DC/DC converter 174, a DC electricheater 96, a DC electric motor 176, and a charge pump 40. The DC/DCconverter 174 can then supply power to the battery charge/loadcontroller 122, which in turn provides power to the battery electricsystem 120, the fan 80 and the discharge pump 42 of the TESS system 10.The battery charge/load controller 122 can also supply power to a lowvoltage VCC system 134, which can be used to provide back-up cooling toboth the TESS system 10 and the conditioned space (i.e. the spacecontaining the cargo). The DC electric heater 96 provides heat to theconditioned space and provides electric defrosting for the TESS system10, including the TESS system's heat exchangers. The DC electric motor176, powers the primary VCC system 132, which is used to providescooling for the TESS system 10 and can be used to directly cool theconditioned space when needed. The system of FIG. 4 also includes a CANBus data module 102 that interfaces with the HTESS electronic controlunit 100. The identification of decelerations or “energy recovery mode”events can be accomplished using CAN Bus data, that data includingvehicle speed, acceleration/deceleration events, and brake applications.The HTESS ECU 100 can use the data to switch between “energy recoverymode” from deceleration events and energy supply from the hybrid DCwheel motor generator 170.

The system shown in FIG. 4 also includes solar panels 144 as anauxiliary power unit, supplying auxiliary power to the batterycharge/load controller 122, which in turn can charge the batteryelectric system 120 and enable the powering of critical systemsincluding the fan 80 and the discharge pump 42 of the TESS system 10,and the low voltage VCC system 134. At the heart of the system shown inFIG. 4 is the thermal storage device 20 (ESPCM reservoir) of the TESSsystem 10, which provides cooling for the conditioned space.

FIG. 5 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) where hybrid truck power is utilized to providehigh voltage DC 172 to a DC/DC converter 174, a DC electric heater 96, aDC electric motor 176, and a charge pump 40. The DC/DC converter 174 canthen supply power to the battery charge/load controller 122, which inturn provides power to the battery electric system 120, the fan 80 andthe discharge pump 42 of the TESS system 10. The battery charge/loadcontroller 122 can also supply power to a low voltage VCC system 134,which can be used to provide back-up cooling to both the TESS system 10and the conditioned space (i.e. the space containing the cargo). The DCelectric heater 96 provides heat to the conditioned space and provideselectric defrosting for the TESS system 10, including the TESS system'sheat exchangers. The DC electric motor 176, powers the primary VCCsystem 132, which is used to provides cooling for the TESS system 10 andcan be used to directly cool the conditioned space when needed. Thesystem of FIG. 5 also includes a CAN Bus data module 102 that interfaceswith the HTESS electronic control unit 100. The identification ofdecelerations or “energy recovery mode” events can be accomplished usingCAN Bus data, that data including vehicle speed,acceleration/deceleration events, and brake applications. The HTESS ECU100 can use the data to switch between “energy recovery mode” fromdeceleration events and energy supply from the hybrid DC wheel motorgenerator 170.

The system shown in FIG. 5 also includes solar panels 144 as anauxiliary power unit, supplying auxiliary power to the batterycharge/load controller 122, which in turn can charge the batteryelectric system 120 and enable the powering of critical systemsincluding the fan 80 and the discharge pump 42 of the TESS system 10,and the low voltage VCC system 134. At the heart of the system shown inFIG. 4 is the thermal storage device 20 (ESPCM reservoir) of the TESSsystem 10, which provides cooling for the conditioned space.

FIG. 6 is a schematic illustration of a mobile hybrid thermal energystorage system (HTESS) where high voltage AC/DC power is provideddirectly from the truck power takeoff device (PTO) generator 190 via the3-phase electric gen-set 192.

The 3-phase electric gen-set 192 provides high voltage AC to an AC/DCpower supply 164, an AC electric heater 94, an AC electric motor 166,and a charge pump 40. The AC/DC converter 164 can then supply power tothe battery charge/load controller 122, which in turn provides power tothe battery electric system 120, the fan 80 and the discharge pump 42 ofthe TESS system 10. The battery charge/load controller 122 can alsosupply power to a low voltage VCC system 134, which can be used toprovide back-up cooling to both the TESS system 10 and the conditionedspace (i.e. the space containing the cargo). The AC electric heater 94provides heat to the conditioned space and provides electric defrostingfor the TESS system 10, including the TESS system's heat exchangers. TheAC electric motor 166, powers the primary VCC system 132, which is usedto provides cooling for the TESS system 10 and can be used to directlycool the conditioned space when needed. The system of FIG. 6 alsoincludes a CAN Bus data module 102 that interfaces with the HTESSelectronic control unit 100. The identification of decelerations or“energy recovery mode” events can be accomplished using CAN Bus data,that data including vehicle speed, acceleration/deceleration events, andbrake applications. The HTESS ECU 100 can use the data to switch between“energy recovery mode” from deceleration events and energy supply fromthe mechanical constant output speed mechanical device 160.

The system shown in FIG. 6 also includes solar panels 144 as anauxiliary power unit, supplying auxiliary power to the batterycharge/load controller 122, which in turn can charge the batteryelectric system 120 and enable the powering of critical systemsincluding the fan 80 and the discharge pump 42 of the TESS system 10,and the low voltage VCC system 134. At the heart of the system shown inFIG. 3 is the thermal storage device 20 (ESPCM reservoir) of the TESSsystem 10, which provides cooling for the conditioned space.

Turning to FIGS. 7 and 8, heating systems are shown in more detail. InFIG. 7 the high-power over-the-road and shorepower portion of theheating system is presented. The OTRHPS or SPHPS provide power toresistive heaters and provide direct heating to the conditioned spaceover the road or while plugged in.

In FIG. 8, the novel idle heating system is presented. To provideheating when HPS is not immediately available, such as when idling orstaging in cold weather and not plugged in, the novel HTESS idle heatingsystem uses a combined electrical and chemical heating system, alsocalled a battery-based combined heat and power system. This combinedheat and power battery system is shown at the high temperature batterypack level. In cold weather when non-HPS heating is anticipated, theHTESS controller employs high temperature batteries (HTB) (such assodium nickel chloride batteries (Zebra) in a high temperature batteryheating system (HTBHS) to provide heating. When use is anticipated, suchas ambient temperatures dropping below a set point, the electric heaterdriven by the OTRHPS, the SPHPS or the HTB itself is commanded by theECU to preheat or maintain heat of the HTESS (HTB) cooling reservoir ofthe HTBHS to achieve operating temperature of the battery (which isotherwise inert as it begins electrical operation at 300 C). A sodiumnickel chloride battery, for example, has to be maintained at aninternal operating temperature of between 270° C. and 350° C. forefficient operation. While the battery is being used, this causes noenergy penalty since the internal resistance of the Zebra batterycoverts resistive losses to heat with 100% efficiency. All batterieshave internal resistance and in all batteries, this internally generatedheat has to be removed by a cooling system to prevent overheating.Therefore in the case of the Zebra battery, the heat generated duringoperation can be used to maintain the temperature as well as externalheating. During non-HPS operating periods, the HTB provides direct airheating to the conditioned space through a dc resistance heater and itsown exothermic reaction to the HTB cooling reservoir and an air (orother) heat exchanger. The HPS, stores electrical and heat energy at asignificantly higher energy density (KJ/KG), (KJ/m3) than any known “hotPCM” material. The HTB also has several key advantages in addition tothe energy storage density. Unless preheated, it is inert and retains acharge for very long periods of time, so for example, during hotseasonal periods of time when the HTB heating energy is not required toheat the conditioned space, the HTB remains off. During heating season,the HTB takes several days to cool off and can maintain its owntemperature eliminating the need for any active charging. In anadvantageous embodiment a zebra HTB converts electrical to heat energyat 100% efficiency and although discharge efficiencies are in the 75%range, when used as a combined heat and power device, an HTB can providewell over 85% efficiency. While not completely ideal, it can be seenthat the SPHPS and OTRHPS heating element could also be provided to theTESS reservoir for use as thermal storage in a more conventionalfashion.

The HTESS offers numerous advantages over a system using only a TESS.The HTESS fully eliminates the diesel engine from TRU while maintainingvirtually unlimited range over the road. The HTESS also provides a netzero or net reduction in trailer weight and consumed volume. Whilestationary, HTESS provides a 1-3 hr. cooling (and heating) window wherethe TRU or VCC power does not need to be plugged in. For continuousoperations with short duration loading, no plug in is needed. Forextended shorepower refrigeration periods, the HTESS extends the rangewhereby the compressor does not need to cycle on. This simplifies theshorepower load demand management. The HTESS allows practicalover-the-road electrical heating function for trailers during coldweather. (TESS BES System is capable to provide only defrost) Advantagesover systems prior to the development of the TES system herein includethat the HTESS does not require diesel APU. It also does not requireexpensive, heavy, large battery systems or a connection to the truck.The HTESS provides heating and cooling functions for the necessaryentire service period without plugging in. It also provides high voltageand power source over the road capable to drive existing type electricTRU VCC systems.

By adopting an HTESS system as an enhancement to a TES system, theBattery Electric System (BES) can be made smaller due to over-the-roadpower and solar power. The HTESS also allows for direct power of VCC forcharging of the TESS and cooling cabin with conventional VCC. Aredesigned compressor system for smaller capacity is also possible dueto HTESS capacity. The HTESS also includes additional controls to managestate of charge and power from various sources.

The HTESS provides a novel high voltage over-the-road power source usinga wheel/axle motor/generator. In one embodiment, a hydraulic axle pumpor driveshaft pump develops hydraulic pressure to drive hydraulic motor,which drives gen-set to power VCC/TESS. Alternatively, a mechanicalconstant speed drive system for genset through CVCVT can be employed.Constant speed (velocity) output of axle or driveshaft throughcontinuously variable transmission can result in a steady source ofpower. Also, a commercial wheel motor product for hybrid vehicles(Protein Electric) can be adopted. DC power can be applied to a secondDC motor to mechanically drive VCC refrigeration components, such as thecompressor TESS. A low voltage system can be provided through a DC/DCinverter to power TESS and BES functions. A high voltage hybrid truckpower, or genset power can also be used as a high voltage power sourcebut these are not optimal embodiments as they require tethering to amating truck at all times for operation.

Hybrid vehicles, such as hybrid automobiles, often recapture energy onlyupon braking. Under such a scenario power, such as to charge the TESsystem, would only be made during braking events. The present hybrid TESsystem would charge the BES batteries and TESS PCM with the truck enginemaking power. So again, traditional hybrid vehicles will not chargebatteries when the engine is making power, only while decelerating.

So for example, according to aspects of the present invention, a TESsystem could first utilize a grid-based charge-up. Once the system ischarged. The TES system could operate in a mixed mode (charge depletingand charge sustaining) or a singular charge-sustaining mode. Thecharge-sustaining mode could be utilized for critical cargo. It wouldmaintain a fully-charged system over the road and would ignore thepossibility for recovering energy due to deceleration. Truck power (ordeceleration power) would be used mechanically drive the generator. Somesmall incremental fuel expense at the truck is used to charge the TESS.

An alternative mixed-mode would have charge-depleting with a chargesustaining setpoint. This would allow for a normal or high efficiencyoperation.

Under normal efficiency the TES system can be fully charged from gridpower. The TESS then cools the conditioned space until 70% charge levelis reached, for example. Over the road power would then maintain aminimum target TESS state of charge (e.g. 70%) always. Truck power couldbe used if needed, but the HTESS can take advantage of decelerationenergy between the setpoint (e.g. 70%) and 100%. Deceleration events areallowed to charge the TESS back to 100%. Below 70% the truck power wouldalso charge the HTES system, along with deceleration charging the HTESS.This creates less chance for truck power/fuel to be used.

Under a high efficiency mode, initial charging could occur using gridpower and use only deceleration events to charge TESS to lower setpointunder normal operating conditions. The controller would allow the systemto deplete the majority of the TESS energy before using truck power tocharge the system and to the extent that the deceleration events werenot sufficient to maintain the system within the desired range. Such amanagement scenario should maximize the savings, but with the risk thatthe TESS storage runs low. Under this scenario a low charge sustainingvalue could be set (e.g. 20% which can cover normal operationalvariation), which would require a good knowledge of the operatingconditions for a particular application to insure that TESS storage isadequate. This creates a minimal chance for using truck power for thelowest fuel usage and consumption.

The identification of deceleration or “energy recovery mode” from can beaccomplished using CAN Bus data, including vehicle speed,acceleration/deceleration events, and brake applications such as aredefined in truck/trailer CAN definitions. SAE J1939, ISO 11992-1.

Summary of TESS Case Examples:

Grid-based Charge-up: Once charged, operate in charge depleting orcharge sustaining for TESS.Charge-sustaining Critical Cargo: Fully-charge and maintain the HTESS atfull charge immediately over the road so ignores the possibility forrecovering energy due to deceleration. Truck power is used to pull thegenerator and uses some small incremental fuel at the truck.Charge Sustaining Normal: Maintain a minimum target TESS state of charge(e.g. 70%) always. Uses truck power if needed, but takes advantage ofdeceleration energy. Allows more efficient operation. (If fully chargedfrom grid power, TESS cools the load until 70% charge is achieved forexample. Deceleration events are allowed to charge the TESS back to 100%and below 70% truck power charges the TESS.)Charge Sustaining High Efficiency: Charge using grid and use onlydeceleration events to charge TESS. Deplete the Majority of the TESSenergy before using truck power to charge. Should maximize the savingswith some risk that the TESS storage runs low. Likely to set a lowcharge sustaining value (e.g. 20% which can cover normal operationalvariation).

Components are also provided for low voltage stationary andover-the-road power. This can be accomplished via wheel/axle high powerconversion or inversion and provides volt power to battery load andcharge controller, which charges the BES and directly may power the TESSelements (except generally the VCC refrigeration compressor motor).Solar power can be used to augment the wheel/axle motor power anddirectly power TESS elements at idle and therefore further minimize BESsystem size and cost. A small APU can be provided as backup for lowvoltage functions. Low voltage truck alternator power can also be used,but is not the optimal solution for reasons such as those disclosedherein.

Also provided in the context of the HTES system is a high temperaturebattery (HTB) system employing a battery [such as zebra battery,sodium-nickel-chloride] whereby electrical energy is taken for use in aresistance heater from the HTB and thermal electrochemical energy isalso taken from HTB for heating. An electrochemical combined heat andpower system. The sodium-nickel-chloride battery, also known as ZEBRAtoday is being used successfully in many applications.

ZEBRA has a nominal cell voltage of 2.58 volts and an specific energy of90-120 Wh/kg, a level comparable with Li-manganese and Li-phosphate. Theservice life is about eight years and 3,000 cycles. It can befast-charged, is non-toxic and the raw materials are abundant andlow-cost. ZEBRA batteries come in large sizes of 10 kWh or higher andtypical applications are forklifts, railways, ships, submarines andelectric cars. Over the road high power system (OTRHPS) or SPHPSprovides the initial heat energy and the batteries take 2-3 days tocool, which for well-managed fleet use in cold climates means verylittle cycling. This allows direct heating the air of the container withhigh voltage coils over the road with traditional TRU methods (highpower heating element). Alternatively, electric or gas or other moreconventional direct heating of cold PCM or other storage medium can beemployed. (Not PCM in Heat Mode).

TES System:

The present invention provides systems and methods for a Thermal EnergyStorage System (“TES system” or “TESS”) that is characterized by rapidcharging of the TESS and then providing portable, self-powered,multi-temperature refrigeration control for large, mobile transportenclosures. The TES system of the invention is capable of providingefficient refrigeration control across a wide range of temperaturesincluding the temperature range of 40° F. to −20° F., as required inmany important refrigerated cargo applications. To accomplish thiscooling, a fan system passes air over a heat exchanger containingflowing eutectic slurry phase change material (ESPCM), so as to cool theair prior to it being provided into the compartment of the mobilerefrigerated transport truck. The ESPCM flow rate is managed by a systemof pumps and valves to control the forced convection cooling effect in aclosed loop fashion.

The system is presented in the context of a large, refrigerated trucktrailer units, which are typically rectangular cuboids 53 feet inlength, 99 inches in width and 110 inches in height, with a cubiccapacity of 1,050 feet, but the system will find application in a widevariety of large, mobile enclosures requiring efficient cooling, such assea containers, box trucks, rail systems and buses, and for thetransport of cargo and passengers.

In an exemplary configuration the TES system employs a Eutectic SlurryPhase Change Material (ESPCM), at least one air-to-liquid heat exchanger(ESPCM/AIR), at least one ESPCM slurry generator (ESPCM_GEN), a batteryenergy storage system (“BES system” or “BESS”), a fan system, a workingfluid (WF), two circulation pumps for circulating the ESPCM and theworking fluid, and an Electronic Control Unit (ECU) to manage theoperation of the system.

The TES system employs phase change materials (PCMs) to store anddeliver cooling power. The TES system has a “charging” side and a“discharging” side. The charging side “charges” the ESPCM when heat isabsorbed by the WF from the PCM. The discharging side “discharges” bycooling the cargo and absorbing heat.

On the discharging side of the TES system, the ESPCM is stored as aslurry in an ESPCM reservoir. The reservoir is in fluid communicationwith an ESPCM air-to-liquid heat exchanger, allowing ESPCM slurry/liquidto circulate between the reservoir and the heat exchanger. The ESPCMpump drives the circulation of the ESPCM liquid. The return ESPCM liquidfrom the exchanger to the reservoir is sprayed on top of the ESPCMslurry to provide nearly infinite heat transfer. The fan system and pumpsystems are powered by the BES system. Temperature control is providedby increasing and decreasing the ESPCM pump flow through the ESPCM/AIRexchanger and by controllably adjusting the fan speed. Defrost energy isminimized by reversing the flow of the ESPCM liquid across the ESPCM/AIRexchanger and managing ESPCM flow rate and direction. A high densitybattery energy storage (BES) system in combination with an electroniccontrol unit (ECU) can provide electrical power and operational controlfor the ESPCM pump, air fans, ECU, controls and defrost heat, asnecessary.

As mentioned above, the TES system employs phase change materials (PCMs)to store and deliver cooling effect or power. One advantageous aspect ofthe system is its ability to apply a variety of PCMs, but withoutongoing adjustment of PCM materials to achieve various targettemperatures once a PCM is applied. When used for a large refrigeratedtruck trailer unit, where the duration between charges may be around 8hours, the TES system provides the necessary electric power and thermalcooling to cool the load during shipment without the use of a combustionengine auxiliary power unit (APU). The term “charge”, as used herein,refers not only to the more traditional notion of energizing a batteryor other electrical storage device by passing a current through it inthe direction opposite to discharge, but also to “charging” the thermalenergy storage device through the removal of heat from the PCM, whichthen allows the PCM to remove heat from the surroundings in “discharge”mode by absorbing heat such as from the compartment of a trailer. In thecontext of longer duration applications, such as found in shipping usingsea containers, where goods may be stored for long durations withcooling using electrically powered refrigeration, the TES system enablesimproved power management during transport and minimizes peak electricalpower requirements by providing cooling during interim periods where theelectrically-powered refrigeration system is shut down or in stand-by.The duration of cooling for any given TES system will be influenced by anumber of factors including the target temperature, the volume of spaceto be refrigerated, and the amount and state of charge of the ESPCM.

The present invention further proposes the use of efficient slurrysystems for trailer and transport refrigeration with the slurrygenerated onboard via a slurry generator heat exchanger and appropriatePCM material and additives, or a combination heat exchanger mechanicaldevice slurry generator. The slurry generator in an advantageousembodiment of the present invention consists of a PCM to working fluidheat exchanger and associated PCM and working fluid flow controls. Togenerate slurry during charging of the TESS in this advantageousembodiment, the highly chilled working fluid is passed through theslurry generator, which is a ESPCM-to-WF heat exchanger. The heatexchanger, designed for high levels of heat transfer and slurry iceformation, along with the intrinsic nature of the selected PCM material,work in combination to form ice crystals on the ESPCM side of the heatexchanger. Most of these crystals, due to their buoyancy, float awayfrom the heat exchanger surface into the bulk ESPCM slurry in the ESPCMstorage and are held beneath the slurry surface by a mesh screen orother means. Some of the ice crystals will have a tendency to remain onthe ESPCM/WF heat exchanger. While some formation is acceptable, largecrystal formations will reduce the efficiency of heat transfer betweenthe working fluid and the ESPCM and are therefore undesirable.

The flow control of the slurry generator is designed to manage thesystematic removal of sticking ice crystals. This is managed via twoflow control paths. On the working fluid side, flow reversal and flowregulation control is performed periodically. On the ESPCM side the flowis managed to cause ice crystals to be removed by the mechanical flowwork of the moving ESPCM slurry. The working fluid flow control takesadvantage of the intrinsic nature of tube and fin heat exchangers inwhich the outlet of the exchanger is slightly warmer than the outlet dueto heat absorption. When the WF flow is reversed ice crystals forming atone end of the exchanger will have a reduced propensity to stick to theheat exchanger surface due to the slight change in the surfacetemperature. The WF flow rate can also be managed to insure that theprocess is effective. The ESPCM flow management in the slurry generatortakes advantage of the kinetic energy of the PCM slurry flow to removethe crystals from the surface and to improve the homogeneity of themixture. In the figures, this flow path of the ESPCM 22 is through thepump 40, across the bypass valve 50 and returning directly to the ESPCMstorage 20.

In a possible embodiment of the present invention slurry generator, adissolved gas system, such as CO₂ can be incorporated into the ESPCMslurry generator. (See e.g. FIG. 30) The dissolved gas system wouldconsist of a high pressure and low pressure dissolved gas tank, acompressor and associated valves and controls. When the ESPCM is nearlydischarged, the dissolved gas system would expose the ESPCM to highpressure gas to saturate it. Using CO₂ and water as an example, thedissolved CO₂ gas would provide sub-cooling capability for the waterESPCM due to its physical effect on water and other liquids. CO₂saturated water for example freezes at a lower temperature than non-CO₂saturated water. The sub-cooled ESPCM at high CO₂ pressure would then bereduced to a lower pressure causing immediate slurry formation as thesub-cooling effect is lost. The release of the CO₂ from the liquidcauses this effect. The lower pressure CO₂ would be captured in the lowpressure CO₂ storage and pumped into the high pressure CO₂ storage.Alternately, while not the most optimal embodiment, CO₂ or CO₂impregnated PCM could be purchased commercially in high pressurecontainers and vented to atmosphere during slurry generation,eliminating the pumping loop complexity. This dissolved gas slurrygenerator can also be applied to typical land-based TES systems, whichuse water to improve their PCM charge density and thus footprint. Mostland-based TES freeze water on tubes, leaving much unfrozen water, whichreduces the cooling storage density. The dissolved gas slurry system canprovide higher thermal charge density as well as higher and more stableheat transfer rates due to the nature of slurry discharge.

Another possible embodiment of the present invention slurry generator isthe use of anti-freeze proteins or other sub-cooling additives to theESPCM to sub-cool and make homogeneous the ESPCM slurry. Antifreezeproteins are used to suppress the freezing temperature of liquids andhave been used commercially with FDA approved-ice cream, indicating thefood safe nature. By suppressing the freezing temperature, and retainingthe melting temperature of liquids, the proteins provide a hysteresistemperature window for charging and discharging the ESPCM, which canimprove the cooling state of charge, or charge density, and simplify thecooling state of charge detection.

While ESPCM/WF heat exchangers are generally the smallest and lightestapproach to slurry generation, they are also generally more complex andrelatively more expensive than other slurry generation systems whichemploy mechanical ice scraping. In one advantageous embodiment of thepresent invention slurry generation of the TESS system can justifyrelatively higher cost slurry generating heat exchangers due to thecritical mobile need for minimized weight, high cooling density,charging speed, efficiency, and large cooling capacity. The conventionalland and marine-based slurry generation systems generally have theobjective of slurry output capacity vs. cost and less focus on weightand slurry state of charge, or slurry density. The non-mechanical slurrygenerator is therefore is not generally used for ground-based, andship-based systems, which have much broader space and weightconstraints. These land and ship based systems generally use mechanicalslurry generators or choose even lower cost non-slurry systems as aconscious trade off for system simplicity.

While the non-mechanical slurry generator is an advantageous embodiment,other mechanical slurry generators are also possible embodiments to theslurry generator of the present invention. Another possible embodimentof the slurry generator is taking the cooling energy to generate slurrydirectly from the VCC refrigeration 14 instead of through the presentinventions working fluid 32 path.

In an alternate embodiment to the present invention, the slurrygenerator would have a working fluid-to-ESPCM heat exchanger, which alsoincludes a mechanical ice scraper function. In this embodiment, the iceand ice crystal formation on the ESPCM/WF exchanger would be augmentedby mechanical ice scraping. The mechanical ice scraper would be drivenby an electric motor powered by shore power or other high power system.The mechanical system could also be powered by alternative powersystems.

In another embodiment, the slurry generator heat exchanger of thepresent invention could be directly coupled to the VCC system. Thisprovides the advantage of one less cooling loop temperature drop, buthas some potential drawbacks, such as high use of VCC refrigerant, andlimited ability to manage ice removal at the evaporator surface withoutmechanical means. VCC refrigerants are expensive and becoming regulatedworldwide to limit their use due to harmful effects to the environment.Large amounts of VCC refrigerant are needed to bring the cooling to theload in multi-zone distributed systems so it is desirable to use a TESSWF approach to minimize the VCC fluid use. Additionally, the need formechanical work to remove the ice crystals from the VCC evaporator in adirect VCC/ESPCM exchanger adds weight and complexity to the system.Recognizing their disadvantages, these direct VCC-coupled embodimentsmay be desirable if it is desired to maximize temperature performance byeliminating the working fluid cooling loop. Each heat exchanger loopgenerally requires a “delta T” or temperature difference to insure heatexchanger efficiency, so more loops in the system results in less usabletemperature capacity in the cooled space. A typical minimum delta T isabout 10° C.

Ice slurry systems produce small particles of ice within a solution,often using additives, such as glycol and water, in the solution. Theresulting ice slurry solution is a slushy mixture that retains aspectsof its fluid characteristics such that it can be pumped through asystem. Because of its characteristics, ice slurry generators do notsuffer from the thermal charging efficiency degradation seen in manyother systems that occurs as ice builds up on an evaporator surface.

In ice slurry systems, ice particles are generated by passing a weakglycol/water or other PCM solution through tubing that is surrounded byan evaporating refrigerant, or as in the preferred embodiment of theinvention a highly cooled working fluid ice particles form as theglycol/water or other PCM solution is cooled by the evaporatingrefrigerant or the WF flow The resulting slush can either form in ordrop directly into a storage tank or be pumped into a storage tankdepending on the system configuration. Ice-free glycol/water or otherPCM solution can then be pumped from the storage tank. Discharge isaccomplished by pumping the cool solution from the tank either directlythrough the cooling load or through an intermediate heat exchanger thatisolates the cooling load from the ice slurry system. The resultingsolution that has been warmed, such as by passing through a heatexchanger, is then returned to the top of the tank and distributed overthe ice slurry via multiple spray nozzles.

One characteristic of ice slurry is the small size of the resultingparticle. Due to the small size of the particle, the ice slurry canresult in better heat transfer between the solution and the ice whencompared to either ice harvesting or ice-on-coil systems which aretypically used in marine or land-based TES. Like an ice harvester, iceslurry systems have relatively high fixed costs associated with theevaporator or ice generator component, but relatively low incrementalcosts as storage capacity is added.

A VCC refrigeration system can be used to charge the ESPCM. The VCCrefrigeration system can be onboard the trailer for a self-containedsystem, or use off-board communication with a multistage refrigerationdevice for higher Coefficient of Performance (COPR) and the possibilityto take advantage of off-peak charging. A liquid working fluid (WF)interfaces between the VCC and the ESPCM to charge the ESPCM, thusproviding the cooling capacity transfer function between the VCC and theESPCM. The WF is supplied as a pumped liquid which simplifies andexpedites the onboard and off-board charging function, maximizing theflow and heat transfer with forced convection to the ESPCM, whilereducing the cost of the pumping system for on and off board systems.

The operation of large cargo/shipping containers, whether they aretrucks, trains, planes, buses, ships, etc., can be divided into twophases: (1) time spent actually in transit and (2) time spent with thecargo, goods or passengers where the vehicle is not in transit but thecargo is nevertheless under the control of the vehicle, such as a shipin dock or a truck at a truck stop. During these non-transit times,external power sources will often be available that can be used tore-charge the systems, and at a fraction of the cost of using theon-board power systems. These non-transit power sources are referred toherein as “shorepower,” which includes the traditional definition of theprovision of shoreside electrical power to a ship at berth while itsmain and auxiliary engines are turned off, but applies more generally tothe provision of power by an external power source to recharge thecooling system of the vehicle. While the system is plugged intoshorepower, the BES can rapidly charge and the ESPCM slurry can bequickly produced by the ESPCM slurry generator. Charging coolingcapacity is provided by a vapor compression cycle (VCC) refrigerationsystem or other means on-board (FIGS. 1, 10, and 12) or off-board thetrailer (FIG. 11). The fully-charged ESPCM and the BES system can thenprovide effective multi-temperature cooling to the refrigerated spaceduring transport without the operation of the VCC refrigeration system,or the need for power from the TRU APU.

Many hours of cooling capacity and significant refrigeration temperaturecontrol for space cooling can be achieved using a flowing eutecticslurry phase change material (ESPCM) with a very low freezingtemperature. The addition of a dedicated high energy density (KJ/KG) BESsystem, such as Li-ion batteries, can allow for independent operationand multi-temperature control without the need for VCC operation, ortruck engine power during over-the-road during transport. The system ispractical to use with current PCMs and the high-energy mass and powerdensity lithium-ion BES system can be sized to power fans and accessoryelectric heating/defrost elements depending upon the application.

Turning to the figures, FIG. 1 provides an overview of an exemplary TESmobile refrigeration system 10. The TES system 10 includes a dischargingloop 12 and a charging loop 13. The discharging loop 12 and the chargingloop 13 share an insulated ESPCM reservoir 20, containing an ESPCM 22,which is stored as a slurry in the ESPCM reservoir 20. By “ice slurry”or “slurry” it is meant a mixture of small ice particles and carrierliquid. Ideally, the slurry is a homogenous mixture of small iceparticles and carrier liquid dispersed throughout the reservoir, but inpractice the mixture is often stratified with the ice tending towardsthe top of the reservoir. The liquid can be either pure freshwater or abinary solution consisting of water and a freezing point depressant.Sodium chloride, ethanol, ethylene glycol and propylene glycol are fourmost commonly used freezing point depressants in industry. Thegeneration and application of ice slurries is discussed in more detailby Kauffled, M. et al., Int J Refrig. 2010 Dec. 1; 33(8): 1491-1505. TheESPCM will be in a semi-liquid state due to a temperature at roughly thetransition point between solid and liquid. The discharging loop 12 usesthe ESPCM 22 to absorb heat from the surroundings thereby allowing theESPCM to effect the cooling of a cargo during shipment, while thecharging loop 13 absorbs heat from the ESPCM 22, usually while thesystem is plugged into shorepower, or otherwise not in transit, tofacilitate the further use of the ESPCM 22 in the discharging loop 12.The ESPCM 22 in the reservoir 20 surrounds, and is in contact with, anESPCM slurry generator 30, also referred to as a working fluidreservoir, and contains a working fluid 32. Facilitating heat transferfrom the WF to the ESPCM, and consequent charging of the ESPCM withinthe ESPCM reservoir is a WF-to-ESCPM heat exchanger, also referred to asthe PCM/WF heat exchanger, which maintains separation of the PCM and WFand increases the surface area over which heat exchange between the twocan occur.

The ESPCM reservoir 20 forms a starting point of reference for movingthrough the discharging loop 12. The ESPCM reservoir 20 is in fluidcommunication with an ESPCM fluid pump 40, a bypass valve 50, areversing valve 60, and an ESPCM/AIR heat exchanger 70. A fan system 80and a defrost system 90 are located in proximity to the ESPCM/AIR heatexchanger 70. The components of the discharging loop are powered by abattery electric system 120 or other appropriate source of power. Thedetails of the discharging loop 12 are described in more detail withreference to FIG. 9, below.

The ESPCM slurry generator 30, forms a starting point of reference forthe charging loop 13 and the generator in fluid communication with areversing valve 62, a VCC-to-working fluid heat exchanger 72, aconventional on-board VCC system 132 and a working fluid charging pump42. The VCC-to-working fluid heat exchanger 72 and the conventionalon-board VCC system 132 in combination form the TESS VCC loop 14. Poweris provided to the charging loop 13 by electrical shore power 142, orother suitable electrical source, such as via truck alternator power, asmall auxiliary power unit or through a wheel motor generator. Shorepower 142, also recharges the battery electric system 120 while the TESsystem 10 is in charging mode. The details of the charging loop 13 aredescribed in more detail with reference to FIG. 10, below.

Both the discharging loop 12 and the charging loop 13 are under thecontrol of an electronic control unit 100. Additionally, a state ofcharge detection module 110 monitors the temperature and/or pressure ofthe ESPCM 22 in the ESPCM reservoir 20 during both the charging mode andthe discharging mode.

Turning to FIG. 9, there is shown the discharging loop 12 of the TESsystem 10 of FIG. 1. The discharging loop 12 includes the ESPCMreservoir 20 containing an ESPCM 22. The ESPCM reservoir 20 is in fluidcommunication with the ESPCM fluid pump 40. The ESPCM fluid pump 40pumps the ESPCM slurry/liquid 22 through the discharging loop 12 underthe control of the electronic control unit 100 and under the power ofthe battery electric system 120. The ESPCM fluid 22 is pumped from theESPCM fluid pump 40 to the bypass valve 50. From the bypass valve 50 theESPCM 22 is directed to either the reversing valve 60 or back into theESPCM reservoir 20. The option of flowing back to the ESPCM reservoir isuseful when the TESS system is in charging mode. By flowing the ESPCM 22partially through the discharging loop during charging of the ESPCM 22,solid ice formation on the PCM/WF heat exchanger in the ESPCM reservoir20 can be minimized. The bypass valve 50 is under the control of theelectronic control unit 100.

When the TES system 10 is in cooling/discharge mode, and the dischargingloop 12 is active, the ESPCM slurry 22 is pumped from the bypass valve50 through the reversing valve 60 to the inlet of the ESPCM/AIR heatexchanger 70. The inlets and outlets of the heat exchanger are describedin more detail below with reference to FIGS. 14-16. As the ESPCM 22travels through the ESPCM/AIR heat exchanger 70, the fan system 80effects the circulation of ambient air from the storage compartmentacross the large surface area of the heat exchanger. The circulatingESPCM 22 absorbs heat from the air as it passes over the heat exchanger,thereby resulting in a cooling of the air within the storagecompartment. By varying the flow of the ESPCM 22 through the heatexchanger 70 and/or the speed fan system 80 using the electronic controlunit 100, the TES system, in conjunction with monitoring the temperaturein the compartment, is able to control the refrigeration of the spaceproviding multi-temperature control for the trailer or other enclosure.

The ESPCM/AIR heat exchanger 70, can be referred to more generally as anESPCM-to-target heat exchanger in those situations where the ultimateconditioned space to be cooled is something other than refrigeratedcargo air. For example, the target for cooling could be air or liquidsfor a city bus or boat air conditioner through liquids such as water,and seawater. Additionally the target could be a chilled bulk load suchas milk, juice, compressed gasses etc.

The ESPCM 22 therefore enters the ESPCM/AIR heat exchanger 70 at theheat exchanger inlet and supplies cooling effect absorbing heat energyfrom the air. Under some controlled ESPCM flow conditions and storagecompartment temperatures, the ESPCM 22 enters the ESPCM/AIR heatexchanger 70 at a cooler temperature than it exits the exchanger'soutlet. The increase in temperature of the ESPCM results in atemperature gradient across the heat exchanger. In cooling/dischargemode the ESPCM 22 is pumped from the outlet of the ESPCM/AIR heatexchanger 70 back through another path of the reversing valve 60 to andis returned to the ESPCM reservoir 20 as a liquid that is sprayed on topof the ESPCM slurry in the reservoir. The diverter valve 60, andconsequently the pathways taken by the ESPCM through the valve, is underthe control of the electronic control unit 100. Flow of ESPCM 22 throughthe discharging loop 12, and between the components in the dischargingloop 12, is in the direction indicated by the arrows in FIG. 9.

The TESS slurry ESPCM cooling loop 12 is capable of controllablyoperating in a multi-temperature environment in either an independentcooling mode or a blended VCC/TESS cooling mode. The TES system 10operates with high efficiency due to the slurry generator producingeutectic slurry of a phase change material. The slurry phase change basematerial is advantageously a food-safe product and is selected to havethe proper temperature characteristics to manage multi-temperaturerefrigeration applications. One particularly useful application will bein the transport of perishable food. The ESPCM material also may containadditives, such as antifreeze proteins, propylene glycol, dissolved CO₂or other means to provide rapid and homogenous slurry formation, withthe novel heat exchanger design avoiding the need for mechanical icescraping work and less durable apparatus. Alternately, it can be seenthat traditional VCC mechanical slurry designs used for industrialmanufacture of ice slurry could be adapted for onboard slurrygeneration. Non-exclusive examples of food-safe PCM materials whichresist icing include propylene glycol, various Dynalene products, andCaCl salt brines. For transport applications the use of ice crystalslurries in dynamic ice systems offer inherent advantages in energyefficiency, capacity, and ESPCM transportation. The ice crystals do notadhere to the WF-to-ESPCM heat exchanger (ESPCM Slurry Generator)surface or are continuously removed from the surface by mechanical meansso a heat cycle defrost circuit is not required for the VCC loop. Thecompressor delivers its full capacity to the load at a consistently highefficiency. Furthermore, the ice slurry can be pumped as a liquid orslurry, so the location of the slurry generator is not restricted to aparticular location in the tank, reducing the structural requirementsand storage tank costs.

Managing frost buildup in the ESPCM-to-Air exchanger 70 is critical toperformance. Ice is formed when moisturized air passes the air cooler(evaporator) or in the present invention ESPCM/Air exchanger ofrefrigeration machinery. This effect needs to be kept at a minimum, asit has an adverse impact on the cooling performance of the refrigerationmachinery. Refrigeration machineries provide different options of iceremoval via defrost cycles. The usual defrost cycle is defrost on demand(auto defrost), which minimizes defrosting activity and maximizesperformance. For traditional VCC, “defrost on demand” measures the iceformation via pressure drops or cooling performance changes asdetermined, for instance, by the bulk air temperature or air pressuredrop across the evaporator. Heating coils energize to remove the ice.This is a large electrical load, especially for a battery system toprovide. Vapor compression cycle refrigeration systems do not usually“reverse” to operate in “heat pump” mode as this is too energy and timeconsuming compared to electrical coils. The current invention can beflow-limited to prevent ice formation and reversed to melt withoutresorting to electrical coils, and the large energy consumptionassociated with electrical coils.

Frost buildup on the ESPCM-to-Air exchanger 70 is managed by a flowmanagement system (defrost system 90), which slows and/or reverses theESPCM 22 flow through the ESPCM-to-Air exchanger 70 using ECU control ofthe ESPCM fluid pump 40 flow and/or reversing valve 60 when iceformation is detected or predicted. Ice formation on the airflow pathcan be detected when air path inlet and outlet pressures, or air pathtemperatures across the ESPCM-to-Air exchanger 70 exceed establishedlimits for example, or by other traditional or nontraditional means.Traditional means of frost detection are assessment of pressure dropsacross the air path of the heat exchanger or the change in temperaturefrom one side of the air flow path of heat exchanger to the other sidefor a given set of conditions. The reverse-flow defrost feature takesadvantage of the large heat exchanger design and liquid ESPCM. Duringcertain operating conditions, especially in the temperature range wherefrost will form, the ESPCM-to-Air exchanger 70 can be controlled by theESPCM fluid pump 40 to have a much higher ESPCM outlet temperature thanESPCM inlet temperature resulting in an ESPCM temperature gradient fromone end of the heat exchanger to the other. This is especially true, forexample, when conditioned space temperatures are above freezing andthere are large amounts of water in the air of the conditioned space.The ESPCM inlet end of the heat exchanger air path may be frosting upwhile the ESPCM outlet side is at a higher temperature, which will notsupport frost. By reversing the flow, the outlet becomes the inlet andthe frost is removed or avoided altogether. Alternatively, the defrostsystem can measure pressure drops across the ESPCM-to-Air exchanger 70.Pressure drops across the ESPCM-to-Air exchanger 70 are a result of iceor frost formation on the air path of the heat exchanger 70. Themanagement and reversal of flow, which is possible with liquid ESPCM andnot easily managed with traditional VCC systems, can result in meltingof ice formed on the surface of the outlet sections of the ESPCM-to-Airexchanger 70, while still facilitating cooling at the inlet portion ofthe exchanger. During conditions of minimal or no frost formation, ESPCMfluid pump 40 can be commanded by the electronic control unit 100 toachieve flow rates, which result in optimized cooling. Here thetemperature gradient across the ESPCM-to-Air exchanger 70 is minimized.For conventional VCC systems, electric heat is often required to removefrost with considerable energy expended in the provision of the heat.These conventional defrost heaters can be provided in the presentinvention to expedite the defrost process if needed. However, energydemand can be significantly reduced without those heaters, allowing fora reduction in the size of the battery energy storage system or otherdefrost energy storage medium. In an advantageous embodiment, thedefrost system 90 is under the control of the electronic control unit100 and under the power of the battery electric system 120.

FIGS. 14 through 16 illustrate the application of reversing valve 60 toreverse the flow of ESPCM 22 through the ESPCM-to-Air exchanger 70. FIG.14 illustrates the standard discharge cycle flow through the reversingvalve 60 and the ESPCM-to-Air exchanger 70. ESPCM 22 will travel fromthe bypass valve 50 to reversing valve 60. Once in reversing valve 60,the ESPCM 22 will be routed to inlet 70 a of the ESPCM-to-Air exchanger70. The ESPCM 22 will wind through the ESPCM-to-Air exchanger 70 andexit the ESPCM-to-Air exchanger 70 via outlet 70 b. Upon exiting theESPCM-to-Air exchanger 70, the ESPCM 22 flows back through the reversingvalve 60 on its way back to the ESPCM reservoir 20. Flow of the ESPCM 22is in the direction indicated by the arrows. Additionally, the fansystem 80 blows the warmer, ambient air 80 a from the compartment acrossthe ESPCM-to-Air exchanger 70, which exits the exchanger as cooler air80 b following the exchange of heat between the ambient air 80 a and theESPCM 22.

Note that the terms inlet 70 a and outlet 70 b are relative to thenormal discharge path through ESPCM-to-Air exchanger 70. During reverseflow defrost the ESPCM 22 will enter through outlet 70 b and exitthrough inlet 70 a.

The defrost system 90 monitors the frost buildup on the ESPCM-to-Airexchanger 70 and manages the status in the electronic control unit 100.The reversing valve 60, along with the ESPCM fluid pump 40, the bypassvalve 50, and the fan system 80, are under the control of the electroniccontrol unit 100. After the detection of frost build up, electroniccontrol unit 100 signals the reversing valve 60, resulting in are-routing or diverting of the ESPCM 22 will through the reversing valve60, as illustrated in FIGS. 15 and 16.

FIG. 15 illustrates the defrost discharge cycle flow through thereversing valve 60 and the ESPCM-to-Air exchanger 70. ESPCM 22 willtravel from the bypass valve 50 to reversing valve 60. Once in reversingvalve 60, the ESPCM 22 will be diverted to outlet 70 b of theESPCM-to-Air exchanger 70. The ESPCM 22 will wind through theESPCM-to-Air exchanger 70 and exit the ESPCM-to-Air exchanger 70 viainlet 70 a. Upon exiting the ESPCM-to-Air exchanger 70, the ESPCM 22flows back through the reversing valve 60 on its way back to the ESPCMreservoir 20. Flow of the ESPCM 22 is in the direction indicated by thearrows. Note most importantly that the path taken by the ESPCM 22through the ESPCM-to-Air exchanger 70 has been reversed from FIG. 14 toFIG. 15 as indicated by the arrows entering and exiting the exchanger.FIG. 16 adds the element of a supplemental electric heat defrost system92 to the design shown in FIG. 15.

FIG. 12 illustrates the charging loop 13 of the TES system 10 of FIG. 1.The charging loop 13 includes ESPCM slurry generator 30 containing aworking fluid 32. The ESPCM slurry generator 30 is in fluidcommunication with reversing valve 62. Reversing valve 62, is, in turn,in fluid communication with a VCC-to-working fluid heat exchanger 72.

The reversing valve 62 on the charging side performs a similar functionto the reversing valve on the discharging side; namely the prevention offrost build-up, but in this case the frost buildup to prevent is at theVCC-to-working fluid heat exchanger 72. Solid ice may form at the inletend of the heat exchanger and is not desirable. By reversing the flowthrough the VCC-to-working fluid heat exchanger 72, it is possible tolimit any icing of the heat exchanger and therefore maximize the stateof charge. As ice builds up on the VCC-to-working fluid heat exchanger72, the charging efficiency decreases due to the insulation of the icebuildup slowing and ultimately limiting the level of charging which ispossible.

A conventional on-board VCC system 132 is located in proximity to theVCC-to-working fluid heat exchanger 72, enabling the VCC system toremove heat from the working fluid as it passes through the heatexchanger 72. Here, the VCC represents a traditional vapor compressioncycle refrigeration system utilizing a compressor, condenser, throttlingvalve and evaporator. VCC refrigeration offers two advantageousfeatures. First, the large thermal energy required to change a liquid toa vapor across the throttling valve facilitates the removal of largeamounts of heat from, in this case, the TESS working fluid. Second, theisothermal nature of the vaporization allows extraction of heat withoutraising the temperature of the VCC refrigerant to the temperature ofwhatever is being cooled. This is a benefit because the closer therefrigerant temperature approaches that of its surroundings, the lowerthe rate of heat transfer. The isothermal process allows the fastestrate of heat transfer. For the present invention the VCC to workingfluid heat exchanger is the evaporator of the VCC System. The TES systemof FIG. 12 employs on-board thermal charging by locating the TESS-VCCloop 13 within the TESS unit. A working fluid charging pump 42 is influid communication with a VCC-to-working fluid heat exchanger 72. Thepump drives the working fluid through the system, and moves the workingfluid directly from the pump back to the reversing valve 62. The workingfluid is routed from the reversing valve back to the ESPCM slurrygenerator 30, having completed the complete cycle thorough the chargingloop 13 and arriving at the slurry generator colder than when it left.Electrical power for the charging loop 13 is provided by the shore power142. In particular, the shore power supplies the significant amounts ofpower consumed by the on-board VCC system 132. Shore power 142, alsorecharges the battery electric system 120 while the TES system 10 is incharging mode.

The working fluid can also be a PCM, but the system does not requirethis set-up. The WF selected is generally one that freezes at atemperature lower than the employed ESPCM. Ideally, the WF will have afreezing point about 15° C. or more below the PCM. This results in a WFthat can flow more easily through the system and at a higher rate, inturn maximizing heat transfer to the PCM and minimizing the chargingtime and pump energy. The PCM needs to have a high cooling density(KJ/Kg, KJ/cc) to be practical as a storage medium and will generally bemostly frozen (high % ice) when fully charged. The WF does not have tohave the same energy capacity (cooling capacity/volume). Instead, it ismore important to have heat transfer optimized, which can beaccomplished to a large degree through managing flow rates of the WF.

The discharging loop 12 and the charging loop 13 employ a state ofcharge detection system 110. The state of charge of the ESPCM 22 can bemeasured by monitoring pressure changes in the system, viscosity sensingor other means to insure that the slurry is fully charged for maximumcooling time, while not overcharged and frozen solid. The pressure-basedstate of charge takes advantage of the physical properties of the PCMmaterial when it changes phase. The PCM phase change is accompanied by adefined increase in volume, viscosity, and other parameters. Bydetecting and measuring these parameters, such as the change in volumeor pressure, the state of charge can be determined. Moreover, thethermal storage medium can be charged with the TRU having an on-boardsystem, as in TESS-VCC loop 14, over the road when its state of chargedetection indicates it is needed.

FIG. 11 illustrates an alternative embodiment of the TES systemillustrated in FIG. 1. In particular, the TES system 10 of FIG. 11 ischaracterized by off-board charging of the working fluid by employing anexternal TESS-VCC loop 15. This is accomplished by locating theVCC-to-working fluid heat exchanger 74 and the VCC system 134 externalto the TES system 10 in much the same way that shore power would beavailable when the system is not in transit. Such an arrangement has anumber of benefits. First, it greatly simplifies the TES system andreduces the associated cost by not having a VCC unit onboard. It alsoreduces the weight of the TES system. Locating the VCC-to-working fluidheat exchanger off-board also allows the use of higher efficiency, orcoefficient of performance (COP) refrigeration systems, with furtherpossible advantages of electrical demand management through an off-boardthermal energy storage system employing the working fluid of the presentinvention as the thermal energy storage medium in the land based storagetanks. On the other hand, by having only off-board charging, there is noback-up system for the TESS should the system's charge run out.

The TES system can take advantage of the high COPR off-board chargingand slurry pumping while maintaining a closed onboard system advantages.For off-board charging of the PCM on-board (closed system—e.g. CaCl withfreezing point of −25° F.) can also incorporate a eutectic slurryworking fluid (e.g. another PCM with a lower freezing point than theonboard PCM −35° F. which is in slurry form). This facilitates highefficiency thermal storage off-board and heat transfer to on-boardESTESS while maintaining onboard “closed system” features.

For example, the working fluid (WF) and PCM can be in slurry form.Off-board slurry generators form open systems in which are not closedsystems which are fixed and sealed like the present invention PCM loop.The closed PCM system provides the advantage of a contained and definedslurry mixture percentage and quantity, which facilitates state ofcharge measurement and effective temperature control on discharge. Tocharge the PCM, you would connect the off-board charging system to thetrailer's on-board TESS reservoir, and pump the WF through the WF/PCMheat exchanger or slurry generation system, and then disconnect theoff-board system components when the desired closed system PCM state ofcharge was achieved. The off-board WF could be open system slurry orhighly chilled liquid.

FIG. 12 presents the charging mode of a TES system as shown in FIG. 10,but adds a conventional on-board TRU VCC evaporator-to-air exchanger152. The addition of the evaporator allows the system to function as astandard VCC system, thereby offering a complete back-up cooling system16 for the TES System 10. Additionally, having the standard VCC systemwith evaporator would allow for the charging of the ESPCM at the sametime as cooling of the cargo. FIG. 13 illustrates the cooling loop sideof FIG. 12, with the addition of the supplemental VCC system 17.

FIG. 3 illustrates a mobile hybrid thermal energy systems where amechanical constant output speed drive is used to supply high voltage DCto the TESS system via a DC/DC converter. FIG. 6 shows high voltageAC/DC power used to power the hybrid TESS system. Depending upon thehigh voltage type, an inverter would invert AC to DC, (e.g. 460 3-phaseAC to 24V dc) or a converter would convert high voltage DC to lowervoltage DC. (e.g. 300 V DC to 24 V DC). Wheel motors for hybrids produce200-600 V DC and Gen-sets produce 460 3 phase. Typical TRU units run on460 3-phase so the gen-set would be the simplest adaptation as it candirectly power a conventional electric TRU. The hybrid wheel motor couldbe implemented with a DC motor on the compressor, such as one adaptedfrom automotive applications.

The mobile hybrid thermal energy systems has been designed to use theover the road high power system at reduced voltage to directly powerTESS components at times in most operating situations while moving.However, solar power is also available to power components at reducedvoltage. For example, the system design would allow the use of solarpower to recharge the BES and power the TESS Fans and pumps directly. Inmore extreme embodiments, it is possible that a less powerful VCC orother cooling system (thermal electric) could be added to directlyprovide cooling using power from the solar panels, thus to providingsolar-powered cooling to thermally charge the TESS and/or cool therefrigerated space.

Hybrid TESS System:

DEFINITIONS

A phase-change material (PCM) is a substance with a high heat of fusion.Upon melting or solidifying at a fixed temperature, the PCM isothermallystores or releases large amounts of energy. Heat is absorbed or releasedwhen the PCM changes from solid to liquid and vice versa. This allowsPCMs to function as latent heat storage units. Examples of PCMs relevantto the present TES system include propylene glycol, and salt brines,such as CaCl, paraffins, alphatics and mineral oils, diphenal anddiphenyl oxide blends, perphenyls silicones and the various Dynalenes(particularly Dynalene MV, Dynalene HT and Dynalene 600). CaCl brinesare a particularly advantageous PCM. A eutectic phase-change material isa material that has the property whereby the isothermal phase changefrom a solid to a liquid medium can absorb and dissipate large amountsof thermal energy while remaining at a constant temperature . . . .

By “slurry” it is meant a semi-liquid mixture of the phase changematerial. Slurry ice provides, a phase-changing refrigerant made up ofmillions of ice “micro-crystals” formed and suspended within a solutionof water and a freezing point depressant. Some compounds used in thefield as freezing point depressants are salt, ethylene glycol, propyleneglycol, various alcohols and sugar.

The term “charge”, as used herein, refers not only to the moretraditional notion of energizing a battery or other electrical storagedevice by passing a current through it in the direction opposite todischarge, but also to “charging” the thermal energy storage devicethrough the removal of heat from the PCM, which then allows the PCM toremove heat from the surroundings in “discharge” mode by absorbing heatsuch as from the compartment of a trailer.

The term “shorepower” refers to the provision of external electricalpower to a vehicle at rest while its main and auxiliary engines are notproviding power to the vehicle. More specifically, shorepower isgrid-based electrical power provided to the refrigeration system whilethe trailer or other refrigerated container is parked, such as at a dockor staging area.

The term “port”, as used herein refers to an opening for intake orexhaust of a fluid. The heat exchangers can have two or more portsfunctioning as inlets and outlets for the circulation of fluid thoughthe conduits within the heat exchanger. Inlets and exhausts can bereversed on an exchanger by reversing the direction of flow of a liquidpassing through the exchanger.

Hardware and Software Infrastructure Examples

The present invention may be employ computing platforms that performactions responsive to software-based instructions. The followingprovides an antecedent basis for the information technology that may beutilized to enable the invention.

Aspects of the present invention are described above with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The present invention has been described in particular detail withrespect to various possible embodiments, and those of skill in the artwill appreciate that the invention may be practiced in otherembodiments. First, the particular naming of the components,capitalization of terms, the attributes, data structures, or any otherprogramming or structural aspect is not mandatory or significant; andthe mechanisms that implement the invention or its features may havedifferent names, formats, or protocols. Further, the system may beimplemented via a combination of hardware and software, as described, orentirely in hardware elements. Also, the particular division offunctionality between the various system components described herein ismerely exemplary, and not mandatory; functions performed by a singlesystem component may instead be performed by multiple components, andfunctions performed by multiple components may instead performed by asingle component.

Unless specifically stated otherwise as apparent from the abovediscussion, it is appreciated that throughout the description,discussions utilizing terms such as “processing” or “computing” or“calculating” or “determining” or “displaying” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system memories orregisters or other such information storage, transmission or displaydevices.

The algorithms and operations presented herein are not inherentlyrelated to any particular computer or other apparatus. Variousgeneral-purpose systems may also be used with programs in accordancewith the teachings herein, or it may prove convenient to construct morespecialized apparatus to perform the required method steps. The requiredstructure for a variety of these systems will be apparent to those ofskill in the, along with equivalent variations. In addition, the presentinvention is not described with reference to any particular programminglanguage. It is appreciated that a variety of programming languages maybe used to implement the teachings of the present invention as describedherein, and any references to specific languages are provided fordisclosure of enablement and best mode of the present invention.

Finally, it should be noted that the language used in the specificationhas been principally selected for readability and instructionalpurposes, and may not have been selected to delineate or circumscribethe inventive subject matter. Accordingly, the disclosure of the presentinvention is intended to be illustrative, but not limiting, of the scopeof the invention, which is set forth in the following claims.

All references cited in the present application are incorporated intheir entirety herein by reference to the extent not inconsistentherewith.

The preceding detailed description is of the best currently contemplatedmodes of carrying out the invention. The description is not to be takenin a limiting sense, but is made merely for the purpose of illustratingthe general principles of the invention, since the scope of theinvention is best defined by the appended claims.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall there between. Now that theinvention has been described,

What is claimed is:
 1. An integrated power generation, energy storageand refrigeration system comprising: a plurality of wheels; an axleaffixed to at least one of the plurality of wheels; an electric powergenerator that converts the rotational motion of the wheels intoelectric power; and a thermal energy storage unit having a heatexchanging fluid and a cooling unit to thermally charge the fluid, thecooling unit powered by the electric power generator.
 2. The integratedpower generation, energy storage and refrigeration system according toclaim 1 further comprising a constant output velocity device coupled ata first end to the axle and at a second end to the generator, whereinthe constant output velocity device maintains the rotational powerdelivered to the generator within a prescribed rotational velocity rangeaccording to the efficient operating parameters of the generator.
 3. Theintegrated power generation, energy storage and refrigeration systemaccording to claim 2 wherein the constant output velocity mechanicaldevice is selected from the group consisting of a constant velocitycontinuously variable transmission and a hydraulic pump and motor set.4. The integrated power generation, energy storage and refrigerationsystem according to claim 1 wherein the electric power generator is awheel motor generator.
 5. The integrated power generation, energystorage and refrigeration system according to claim 1 further comprisinga DC-DC converter or an AC-DC inverter and a thermal energy storage lowpower battery electric system, the converter or inverter adapted tofacilitate powering of thermal energy storage components and charging ofthe thermal energy storage low power battery electric system by theelectric power generator and the thermal energy storage low powerbattery electric system adapted to supply auxiliary power to componentsof the thermal energy storage unit or an auxiliary low voltage coolingunit to charge the thermal energy storage system.
 6. The integratedpower generation, energy storage and refrigeration system according toclaim 5 wherein the thermal energy storage unit further comprisescomponents selected from the group consisting of an electronic controlunit adapted to regulate the thermal energy storage unit, a temperaturesensor adapted to monitor the temperature of the heat exchanging fluid,a fan adapted to circulate air in a cargo or passenger space, one ormore pumps adapted to circulate the heat exchanging fluid and divertersadapted to route the flow of the heat exchanging fluid through a heatexchanger, wherein the components are powered by the thermal energystorage low power battery electric system.
 7. The integrated powergeneration, energy storage and refrigeration system according to claim 1further comprising a solar energy collecting unit adapted to supplyauxiliary power to the thermal energy storage unit or to supplyauxiliary power to an auxiliary low voltage cooling unit configured tocharge the thermal energy storage system or cool a conditioned space. 8.The integrated power generation, energy storage and refrigeration systemaccording to claim 7 further comprising a thermal energy storage lowpower battery electric system adapted to be selectively charged by thesolar energy collecting unit and the electric power generator, thethermal energy storage low power battery electric system adapted tosupply auxiliary power to components of the a thermal energy storageunit.
 9. The integrated power generation, energy storage andrefrigeration system according to claim 7 further comprising acontroller module adapted to manage the supply of power between to thesolar energy collecting unit and the electric power generator.
 10. Anintegrated power generation, energy storage and refrigeration systemcomprising: a chassis; a wheel rotatably coupled to the chassis andadapted for contact with a road surface; a constant output velocity unitin rotational communication with the wheel; an electric power generatorin rotational communication with the constant output speed drive unit,wherein the constant output velocity unit supplies rotational power tothe electric power generator within a prescribed range of rotationalvelocity and whereby the generator converts the rotational motion of thewheels into electric power; and a thermal energy storage unit having aheat exchanging fluid and a cooling unit to charge the fluid, thecooling unit powered by the electric power generator.
 11. The integratedpower generation, energy storage and refrigeration system according toclaim 10 wherein the chassis is a trailer chassis adapted to be pulledby a tractor.
 12. The thermal energy storage system according to claim10 wherein the heat exchanging fluid is a phase change material.
 13. Theintegrated power generation, energy storage and refrigeration systemaccording to claim 10 further comprising a solar energy collecting unitadapted to supply auxiliary power to the thermal energy storage unit orto supply auxiliary power to an auxiliary low voltage cooling unitconfigured to charge the thermal energy storage system or providecooling to a conditioned space.
 14. The integrated power generation,energy storage and refrigeration system according to claim 13 furthercomprising a thermal energy storage low power battery electric systemadapted to be selectively charged by the solar energy collecting unitand the electric power generator, the thermal energy storage low powerbattery electric system adapted to supply auxiliary power to componentsof the a thermal energy storage unit.
 15. The integrated powergeneration, energy storage and refrigeration system according to claim10 wherein the thermal energy storage unit further comprises componentsselected from the group consisting of an electronic control unit adaptedto regulate the thermal energy storage unit, a temperature sensoradapted to monitor the temperature of the heat exchanging fluid, a fanadapted to circulate air in a cargo space, one or more pumps adapted tocirculate the heat exchanging fluid and diverters adapted to route theflow of the heat exchanging fluid through a heat exchanger, wherein thecomponents are powered by the thermal energy storage low power batteryelectric system.
 16. The integrated power generation, energy storage andrefrigeration system according to claim 10 further comprising an axlecoupling the wheel to the constant output velocity unit.
 17. Theintegrated power generation, energy storage and refrigeration systemaccording to claim 10 wherein the constant output velocity mechanicaldevice is selected from the group consisting of a constant velocitycontinuously variable transmission and a hydraulic pump and motor set.18. A hybrid-powered regenerative mobile thermal energy storage systemcomprising: a chassis; a wheel rotatably coupled to the chassis andadapted for contact with a road surface, wherein the wheel has a wheelmotor generator for the conversion of rotational mechanical energy ofthe wheel into electrical power; and a thermal energy storage unithaving a heat exchanging fluid and a cooling unit to charge the fluid,the cooling unit powered by the wheel motor generator.
 19. Thehybrid-powered regenerative mobile thermal energy storage systemaccording to claim 18 further comprising a DC-DC converter or an AC-DCinverter and a thermal energy storage low power battery electric system,the converter or inverter adapted to facilitate powering of thermalenergy storage components and charging of the thermal energy storage lowpower battery electric system by the wheel motor generator and thethermal energy storage low power battery electric system adapted tosupply auxiliary power to components of the a thermal energy storageunit or an auxiliary low voltage cooling unit to charge the thermalenergy storage system.